=== Yet Another Related Posts Plugin ===
Contributors: mitchoyoshitaka
Author: mitcho (Michael Yoshitaka Erlewine)
Author URI: http://mitcho.com/
Plugin URI: http://mitcho.com/code/yarpp/
Donate link: https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=66G4DATK4999L&item_name=mitcho%2ecom%2fcode%3a%20donate%20to%20Michael%20Yoshitaka%20Erlewine&no_shipping=0&no_note=1&tax=0&currency_code=USD&lc=US&charset=UTF%2d8
Tags: related, posts, post, pages, page, RSS, feed, feeds
Requires at least: 2.8
Tested up to: 2.9.3
Stable tag: 3.1.6

Returns a list of related entries based on a unique algorithm for display on your blog and RSS feeds. A templating feature allows customization of the display.

== Description ==

Yet Another Related Posts Plugin (YARPP) gives you a list of posts and/or pages related to the current entry, introducing the reader to other relevant content on your site. Key features include:

1. **An advanced and versatile algorithm**: Using a customizable algorithm considering post titles, content, tags, and categories, YARPP calculates a "match score" for each pair of posts on your blog. You choose the threshold limit for relevance and you get more related posts if there are more related posts and less if there are less.
2. **Templating**: **New in 3.0!** The [YARPP templating system](http://mitcho.com/blog/projects/yarpp-3-templates/) puts you in charge of how your posts are displayed.
3. **Caching**: **Improved in 3.1!** YARPP organically caches the related posts data as your site is visited, greatly improving performance.
4. **Related posts in RSS feeds**: Display related posts in your RSS and Atom feeds with custom display options.
5. **Disallowing certain tags or categories**: You can choose certain tags or categories as disallowed, meaning any page or post with such tags or categories will not be served up by the plugin.
6. **Related posts and pages**: Puts you in control of pulling up related posts, pages, or both.

This plugin requires that your database run on MySQL 4.1 or greater.

**Other plugins by mitcho**: [HookPress](http://wordpress.org/extend/plugins/hookpress/), [Plugin Beta Tester](http://wordpress.org/extend/plugins/plugin-beta-tester/), [Distinct Preview](http://wordpress.org/extend/plugins/distinct-preview/), [Markdown for WordPress and bbPress](http://wordpress.org/extend/plugins/markdown-for-wordpress-and-bbpress/), [WP-Smartdate](http://wordpress.org/extend/plugins/wp-smartdate/).

= Testimonials =

"One of my favorite [plugin]s I just activated on my blog is called Yet Another Related Posts Plugin... I've been blogging seven or eight years now so I have a lot of archives, and it actually surprises me sometimes when I blog about something and I visit the permalink to see I've written about it before... and it also increases the traffic on your blog because when they come in just to one entry, they'll see this other stuff going on." - Matt Mullenweg, WordPress creator

"As most [sports betting](http://www.betus.com/) fans use our portal, [BetUS.com Sportsbook](http://www.betus.com/sportsbook/) works hard to maintain a high level of quality on their site.  Mitcho and his amazing plugins help keep us moving our technology forward.  Thank you Mitcho, and the [Wordpress](http://wordpress.org) team for your service and creativity!" - [BetUS.com](http://BetUS.com/)

== Installation ==

= Auto display on your website =

1. Copy the folder `yet-another-related-posts-plugin` into the directory `wp-content/plugins/` and (optionally) the sample templates inside `yarpp-templates` folder into your active theme.

2. Activate the plugin.

= Auto display in your feeds =

Make sure the "display related posts in feeds" option is turned on if you would like to show related posts in your RSS and Atom feeds. The "display related posts in feeds" option can be used regardless of whether you auto display them on your website (and vice versa).

= Widget =

Related posts can also be displayed as a widget. Go to the Design > Widgets options page and add the Related Posts widget. The widget will only be displayed on single entry (permalink) pages. The widget can be used even if the "auto display" option is turned off.

= Custom display through templates = 

New in version 3.0, YARPP allows the advanced user with knowledge of PHP to customize the display of related posts using a templating mechanism. More information is available [in this tutorial](http://mitcho.com/blog/projects/yarpp-3-templates/).

= Manual installation =

For advanced users with knowledge of PHP, there is also an [advanced manual installation option](http://mitcho.com/code/yarpp/manual.php).

== Frequently Asked Questions ==

If your question isn't here, ask your own question at [the Wordpress.org forums](http://wordpress.org/tags/yet-another-related-posts-plugin?forum_id=10#postform). *Please do not email or tweet with questions.*

= Every page just says "no related posts"! What's up with that? =

Most likely you have "no related posts" right now as the default "match threshold" is too high. Here's what I recommend to find an appropriate match threshold: first, lower your match threshold in the YARPP prefs to something very low, like 1. Most likely the really low threshold will pull up many posts that aren't actually related (false positives), so look at some of your posts' related posts and their match scores. This will help you find an appropriate threshold. You want it lower than what you have now, but high enough so it doesn't have many false positives.

= How do I turn off the match score next to the related posts? =

The match score display is only for administrators... you can log out of `wp-admin` and check out the post again and you will see that the score is gone.

If you would like more flexibility in changing the display of your related posts, please see the [templating tutorial](http://mitcho.com/blog/projects/yarpp-3-templates/).

= Does YARPP work with full-width characters or languages that don't use spaces between words? =

YARPP works fine with full-width (double-byte) characters, assuming your WordPress database is set up with Unicode support. 99% of the time, if you're able to write blog posts with full-width characters and they're displayed correctly, YARPP will work on your blog.

However, YARPP does have difficulty with languages that don't place spaces between words (Chinese, Japanese, etc.). For these languages, the "consider body" and "consider titles" options in the "Relatedness options" may not be very helpful. Using only tags and categories may work better for these languages.

= Does YARPP slow down my blog/server? =

A little bit, yes. However, YARPP 3.0 introduced a new caching mechanism which greatly reduces the hit of the computationally intensive relatedness computation. In addition, *I highly recommend all YARPP users use a page-caching plugin, such as [WP-SuperCache](http://ocaoimh.ie/wp-super-cache/).*

If you find that the YARPP database calls are still too database-intensive, try turning off "cross relate posts and pages," not considering tags and/or categories in the Relatedness formula, and not excluding any tags and/or categories in The Pool. All of these will improve database performance.

= I use DISQUS for comments. I can't access the YARPP options page! =

The DISQUS plugin loads some JavaScript voodoo which is interacting in weird ways with the AJAX in YARPP's options page. You can fix this by going to the DISQUS plugin advanced settings and turning on the "Check this if you have a problem with comment counts not showing on permalinks" option.

= I use DISQUS for comments. My RSS feed is now invalid and cannot be parsed by some clients! =

The DISQUS plugin loads some JavaScript voodoo when related posts are displayed, even in the RSS feed. You can fix this by going to the DISQUS plugin advanced settings and turning on the "Check this if you have a problem with comment counts not showing on permalinks" option.

= I get a PHP error saying "Cannot redeclare `related_posts()`" =

You most likely have another related posts plugin activated at the same time. Please disactivate those other plugins first before using YARPP.

= I turned off one of the relatedness criteria (titles, bodies, tags, or categories) and now every page says "no related posts"! =

This has to do with the way the "match score" is computed. Every entry's match score is the weighted sum of its title-score, body-score, tag-score, and category-score. If you turn off one of the relatedness criteria, you will no doubt have to lower your match threshold to get the same number of related entries to show up. Alternatively, you can consider one of the other criteria "with extra weight".

It is recommended that you tweak your match threshold whenever you make changes to the "makeup" of your match score (i.e., the settings for the titles, bodies, tags, and categories items).

= Are there any plugins that are incompatible with YARPP? =

Aside from the DISQUS plugin (see above), currently the only known incompatibility is [with the SEO_Pager plugin](http://wordpress.org/support/topic/267966) and the [Pagebar 2](http://www.elektroelch.de/hacks/wp/pagebar/) plugin. Users of SEO Pager are urged to turn off the automatic display option in SEO Pager and instead add the code manually. Other related posts plugins, obviously, may also be incompatible.

Please submit similar bugs by starting a new thread on [the Wordpress.org forums](http://wordpress.org/tags/yet-another-related-posts-plugin?forum_id=10#postform). I check the forums regularly and will try to release a quick bugfix.

= Things are weird after I upgraded. =

I highly recommend you disactivate YARPP, replace it with the new one, and then reactivate it.

== Localizations ==

YARPP is currently localized in the following languages:

  * Belarussian (`by_BY`) by [Fat Cow](http://www.fatcow.com)
  * Simplified Chinese (`zh_CN`) by Jor Wang (mail at jorwang dot com) of [jorwang.com](http://jorwang.com)
  * Cypriot Greek (`el_CY`) by Aristidis Tonikidis (yarpp-el at mitcho dot com) of [akouseto.gr](http://www.akouseto.gr)
  * Dutch (`nl_NL`) by Sybrand van der Werf (yarpp-nl at mitcho dot com)
  * French (`fr_FR`) by Lionel Chollet (yarpp-fr at mitcho dot com)
  * German (`de_DE`) by Michael Kalina (yarpp-de at mitcho dot com) of [3th.be](http://3th.be)
  * Greek (`el_EL`) by Aristidis Tonikidis (yarpp-el at mitcho dot com) of [akouseto.gr](http://www.akouseto.gr)
  * Hebrew (`he_IL`) by Mickey Zelansky (yarpp-he at mitcho dot com) of [simpleidea.us](http://simpleidea.us)
  * Hindi (`hi_IN`) by [Outshine Solutions](http://outshinesolutions.com/) (yarpp-hi at mitcho dot com)
  * Italian (`it_IT`) by Gianni Diurno (yarpp-it at mitcho dot com) of [gidibao.net](http://gidibao.net)
  * Japanese (`ja`) by myself (yarpp at mitcho dot com)
  * Korean (`ko_KR`) by [Jong-In Kim](http://incommunity.codex.kr) (yarpp-ko at mitcho dot com)
  * Latvian (`lv_LV`) by [Mike](http://antsar.info) (yarpp-lv at mitcho dot com)
  * Lithuanian (`lt_LT`) by [Karolis Vyčius](http://vycius.co.cc) (yarpp-lt at mitcho dot com)
  * Polish (`pl_PL`) by [Perfecta](http://perfecta.pro/wp-pl/)
  * Brazilian Portuguese (`pt_BR`) by Rafael Fischmann (yarpp-ptBR at mitcho.com) of [macmagazine.br](http://macmagazine.com.br/)
  * Russian (`ru_RU`) by Marat Latypov (yarpp-ru at mitcho.com) of [blogocms.ru](http://blogocms.ru)
  * Swedish (`sv_SE`) by Max Elander (yarpp-sv at mitcho dot com)
  * Vietnamese (`vi_VN`) by Vu Nguyen (yarpp-vi at mitcho dot com) of [Rubik Integration](http://rubikintegration.com/)
  * Ukrainian (`uk_UA`) by [Onore](http://Onore.kiev.ua) (Alexander Musevich) (yarpp-uk at mitcho dot com)
  * Uzbek (`uz_UZ`) by Ali Safarov (yarpp-uz at mitcho dot com) of [comfi.com](http://www.comfi.com/)
	
We already have localizers lined up for the following languages:

  * Danish
  * Spanish
  * Catalan
  * Indonesian
  * Hungarian
  * Romanian
  * Swedish
  * Thai

If you are a bilingual speaker of English and another language and an avid user of YARPP, I would love to talk to you about localizing YARPP! Localizing YARPP can be pretty easy using [the Codestyling Localization plugin](http://www.code-styling.de/english/development/wordpress-plugin-codestyling-localization-en). Please [contact me](mailto:yarpp@mitcho.com) *first* before translating to make sure noone else is working on your language. Thanks!

== Changelog ==

= 3.1.6 =
* Added Latvian localization (`lv_LV`)
* Added a template which displays post thumbnails; requires WordPress 2.9 and a theme which has post thumbnail support
= 3.1.5 =
* Quick bugfix to new widget template (removed extra quote).
= 3.1.4 =
* Improved widget code
* Localization improvements - descriptions can now be localized
* [Compatibility with PageBar](http://wordpress.org/support/topic/346714) - thanks to Latz for the patch!
* Bugfix: [`related_posts_exist` was giving incorrect values](http://wordpress.org/support/topic/362347)
* Bugfix: [SQL error for setups with blank DB_CHARSET](http://wordpress.org/support/topic/358757)
= 3.1.3 =
* Performance improvements:
  * Turning off cache expiration, made possible by smarter caching system of 3.1 - should improve caching database performance over time.
  * [updated primary key for cache](http://wordpress.org/support/topic/345070) by Pinoy.ca - improves client-side pageload times.
* Code cleanup
  * Rewrote `include` and `require` paths
* Bugfix: localizations were not working with WordPress 2.9 ([a CodeStyling Localizations bug](http://wordpress.org/support/topic/343389))
* Bugfix: [redundant entries for "unrelatedness" were being inserted](http://wordpress.org/support/topic/344859)
* Bugfix: [`yearpp_clear_cache` bug on empty input](http://wordpress.org/support/topic/343001)
* Version checking code no longer uses Snoopy.
* New localization: Hindi by [Outshine Solutions](http://outshinesolutions.com/)
= 3.1.2 =
* Bugfix: [saving posts would sometimes timeout](http://wordpress.org/support/topic/343001)
= 3.1.1 =
* [Possible fix for the "no related posts" issue](http://wordpress.org/support/topic/284209/page/2) by [vkovalcik](http://wordpress.org/support/profile/5032111)
* Bugfix: [slight optimization to keyword function](http://wordpress.org/support/topic/284209/page/2) by [vkovalcik](http://wordpress.org/support/profile/5032111)
* Bugfix: [regex issue with br-stripping](http://wordpress.org/support/topic/323823)
= 3.1 =
* New snazzy options screen
* Smarter, less confusing caching
  * No more manual caching option—"on the fly" caching is always on now.
* Bugfix: [fixed related pages functionality](http://wordpress.org/support/topic/273008)
* Bugfix: [an issue with options saving](http://wordpress.org/support/topic/312637)
* Bugfix: [a slash escaping bug](http://wordpress.org/support/topic/315560)
* Minor fixes:
  * Fixed `yarpp_settings_link` dependency when disabled.
  * Breaks (<br />) are now stripped out of titles.
  * Added plugin incompatibility info for Pagebar.
  * Faster post saving.
= 3.0.13 =
* Quick immediate bugfix to 3.0.12
= 3.0.12 =
* Yet another DISQUS note... sigh.
* Changed [default markup](http://wordpress.org/support/topic/307890) to be make the output validate better.
* Reformatted the version log in readme.txt
* Added a Settings link to the plugins page
* Some initial WPML support:
  * Tweaked a SQL query so that it was WPML compatible
  * Added YARPP template to be used with WPML
* Added Hebrew localization
= 3.0.11 =
* Quick fix for `compare_version` code.
= 3.0.10 =
* Added Ukrainian localization
* Incorporated a quick update for the widget display [thanks to doodlebee](http://wordpress.org/support/topic/281575).
* Now properly uses `compare_version` in lieu of old hacky versioning.
= 3.0.9 =
* Added Uzbek, Greek, Cypriot Greek, and Vietnamese localizations
* Further bugfixes for the [pagination issue](http://wordpress.org/support/topic/267350)
= 3.0.8 =
* Bugfix: [a pagination issue](http://wordpress.org/support/topic/267350) (may not be completely fixed yet)
* Bugfix: a quick bugfix for widgets, thanks to Chris Northwood
* Added Korean and Lithuanian localizations
* Bugfix: [when ad-hoc caching was off, the cached status would always say "0% cached" ](http://wordpress.org/support/topic/286395)
* Bugfix: enabled Polish and Italian stopwords and [fixed encoding of Italian stopwords](http://wordpress.org/support/topic/288808).
* Bugfix: `is_single` and other such flags are now set properly within the related posts Loop (as a result, now [compatible with WP Greet Box](http://wordpress.org/support/topic/288230))
* Confirmed compatibility with 2.8.2
* Bugfix: [the Related Posts metabox now respects the Screen Options](http://wordpress.org/support/topic/289290)
= 3.0.7 =
* Bugfix: additional bugfix for widgets.
* Reinstating excerpt length by number of words (was switched to letters in 3.0.6 without accompanying documentation)
* Localizations:
  * Updated Italian
  * Added Belarussian by [Fat Cow](http://www.fatcow.com)
* Confirmed compatibility with 2.8.1
= 3.0.6 =
* Bugfix: [updated excerpting to use `wp_html_excerpt`](http://wordpress.org/support/topic/268934) (for WP 2.5+)
* Bugfix: [fixed broken widget display](http://wordpress.org/support/topic/276031)
* Added Russian (`ru_RU`) localization by Marat Latypov
* Confirmed 2.8 compatibility
* Added note on [incompatibility with SEO Pager plugin](http://wordpress.org/support/topic/267966)
= 3.0.5 =
* Added link to manual SQL setup information [by request](http://wordpress.org/support/topic/266752)
* Added Portuguese localization
* Updated info on "on the fly" caching - it is *strongly recommended* for larger blogs.
* Updated "incomplete cache" warning message so it is only displayed when the "on the fly" option is off.
= 3.0.4 =
* A fix to the version checking in the options page - now uses Snoopy
* Adding Dutch localization
= 3.0.3 =
* Reinstated the 3.0.1 bugfix for includes
* Bugfix: Fixed encoding issue in keyword caching algorithm
* Bugfix: One SQL query assumed `wp_` prefix on tables
* Added Polish localization
* Added note on DISQUS in readme
* Making some extra strings localizable
* Bugfix: [a problem with the Italian localization](http://wordpress.org/support/topic/265952)
= 3.0.2 =
* Bugfix: [Templating wasn't working with child templates.](http://wordpress.org/support/topic/265515)
* Bugfix: In some situations, [SQL errors were printed in the AJAX preview displays](http://wordpress.org/support/topic/265728).
= 3.0.1 =
* Bugfix: In some situations before YARPP options were updated, an `include` PHP error was displayed.
= 3.0 =
* Major new release!
* Caching for better SQL performance
* A new [templating feature](http://mitcho.com/blog/projects/yarpp-3-templates/) for custom related posts displays
* Cleaned up options page
* New and updated localizations
= 2.1.6 =
* Versioning bugfix - same as 2.1.5
= 2.1.5 =
* Bugfix: In certain scenarios, [related posts would be displayed in RSS feeds even when that option was off](http://wordpress.org/support/topic/216145)
* Bugfix: The `related_*()` functions were missing the `echo` parameter
* Some localization bugfixes
* Localizations:
	* Japanese (`ja`) by myself ([mitcho (Michael Yoshitaka Erlewine)](http://mitcho.com))
= 2.1.4 =
* Bugfix: [Settings' sumbmit button took you to PayPal](http://wordpress.org/support/topic/214090)
* Bugfix: Fixed [keyword algorithm for users without `mbstring`](http://wordpress.org/support/topic/216420)
* Bugfix: `title` attributes were not properly escaped
* Bugfix: [keywords did not filter tags](http://wordpress.org/support/topic/218211). (This bugfix may vastly improve "relatedness" on some blogs.)
* Localizations:
	* Simplified Chinese (`zh_CN`) by Jor Wang (mail at jorwang dot com) of [jorwang.com](http://jorwang.com)
	* German (`de_DE`) by Michael Kalina (yarpp-de at mitcho dot com) of [3th.be](http://3th.be)
* The "show excerpt" option now shows the first `n` words of the excerpt, rather than the content ([by request](http://wordpress.org/support/topic/212577))
* Added an `echo` parameter to the `related_*()` functions, with default value of `true`. If `false`, the function will simply return the output.
* Added support for the [AllWebMenus Pro](http://wordpress.org/extend/plugins/allwebmenus-wordpress-menu-plugin/) plugin
* Further internationalization: 
	* the donate button! ^^
	* overused words lists ([by request](http://wordpress.org/support/topic/159359))), with a German word list.
= 2.1.3 =
* Bugfix: Turned off [the experimental caching](http://wordpress.org/support/topic/216194#post-894440) which shouldn't have been on in this release...
* Bugfix: an issue with the [keywords algorithm for non-ASCII characters](http://wordpress.org/support/topic/216078)
= 2.1.2 =
* Bugfix: MyISAM override handling bug
= 2.1.1 =
* Bugfix: keywords with forward slashes (\) could make the main SQL query ill-formed.
* Bugfix: Added an override option for the [false MyISAM warnings](http://wordpress.org/support/topic/211043).
* Preparing for localization! (See note at the bottom of the FAQ.)
* Adding a debug mode--just try adding `&yarpp_debug=1` to your URL's and look at the HTML source.
= 2.1 - The RSS edition! =
* RSS feed support!: the option to automagically show related posts in RSS feeds and to customize their display, [by popular request](http://wordpress.org/support/topic/151766).
* A link to [the Yet Another Related Posts Plugin RSS feed](http://wordpress.org/support/topic/208469).
* Further optimization of the main SQL query in cases where not all of the match criteria (title, body, tags, categories) are chosen.
* A new format for pushing arguments to the `related_posts()` functions.
* Bugfix: [compatibility](http://wordpress.org/support/topic/207286) with the [dzoneZ-Et](http://wordpress.org/extend/plugins/dzonez-et/) and [reddZ-Et](http://wordpress.org/extend/plugins/reddz-et/) plugins.
* Bugfix: `related_*_exist()` functions produced invalid queries
* A warning for `wp_posts` with non-MyISAM engines and semi-compatibility with non-MyISAM setups.
* Bugfix: [a better notice for users of Wordpress < 2.5](http://www.mattcutts.com/blog/wordpress-plugin-related-posts/#comment-131194) regarding the "compare tags" and "compare categories" features.
= 2.0.6 =
* A quick emergency bugfix (In one instance, assumed existence of `wp_posts`)
= 2.0.5 =
* Further optimized algorithm - should be faster on most systems. Good bye [subqueries](http://dev.mysql.com/doc/refman/5.0/en/unnamed-views.html)!
* Bugfix: restored MySQL 4.0 support
* Bugfix: [widgets required the "auto display" option](http://wordpress.org/support/topic/190454)
* Bugfix: sometimes default values were not set properly on (re)activation
* Bugfix: [quotes in HTML tag options would get escaped](http://wordpress.org/support/topic/199139)
* Bugfix: `user_level` was being checked in a deprecated manner
* A helpful little tooltip for the admin-only threshold display
= 2.0.4 - what 2.0 should have been =
* Bugfix: new fulltext query for MySQL 5 compatibility
* Bugfix: updated `apply_filters` to work with WP 2.6
= 2.0.3 =
* Bugfix: [2.0.2 accidentally required some tags or categories to be disabled](http://wordpress.org/support/topic/188745)
= 2.0.2 =
* Versioning bugfix (rerelease of 2.0.1)
= 2.0.1 =
* Bugfix: [`admin_menu` instead of `admin_head`](http://konstruktors.com/blog/wordpress/277-fixing-postpost-and-ozh-absolute-comments-plugins/)
* Bugfix: [a variable scope issue](http://wordpress.org/support/topic/188550) crucial for 2.0 upgrading
= 2.0 =
* New algorithm which considers tags and categories, by frequent request
* Order by score, date, or title, [by request](http://wordpress.org/support/topic/158459)
* Excluding certain tags or categories, [by request](http://wordpress.org/support/topic/161263)
* Sample output displayed in the options screen
* Bugfix: [an excerpt length bug](http://wordpress.org/support/topic/155034?replies=5)
* Bugfix: now compatible with the following plugins:
	- diggZEt
	- WP-Syntax
	- Viper's Video Quicktags
	- WP-CodeBox
	- WP shortcodes
= 1.5.1 =
* Bugfix: standardized directory references to `yet-another-related-posts-plugin`
= 1.5 =
* Simple installation: automatic display of a basic related posts install
* code and variable cleanup
* FAQ in the documentation
= 1.1 =
* Related pages support!
* Also, uses `apply_filters` to apply whatever content text transformation you use (Wikipedia link, Markdown, etc.) before computing similarity.
= 1.0.1 =
* Bugfix: 1.0 assumed you had Markdown installed
= 1.0 =
* Initial upload