Scott Taylor

Most ratings plugins contain too much code: inline JavaScript, messy markup, weird CSS. Rate is simple, hardly intrusive, and completely overridable.
A Post/Page/Custom Post Type’s rating is the average of all comment ratings. A user can leave a rating when commenting, and change that rating inline after leaving a comment (if logged-in or Cookie’d).
Don’t be afraid to play around and extend the code: drop a <code>rate.css</code> file in your theme directory and mine won’t even load (by default, Rate stars are transparent with a white border, so you can use <code>background-color</code> to set your stars’ colors)!
<pre><code><?php 
// in this version, you need to insert these functions into your theme for ratings to appear
// you don't have to use the_rating(), the comment_rating() will work by itself, but the_rating() will not

// for a Post, Page, or Custom Post Type (average of all comment ratings)
the_rating();

// for a comment
the_comment_rating();
?>
</code></pre>
Read More: http://scottctaylor.wordpress.com/2010/11/30/new-plugin-rate/

Rate

Most ratings plugins contain too much code: inline JavaScript, messy markup, weird CSS. Rate is simple, hardly intrusive, and completely overridable.

Dwenaus

BuddyPress 1.6 compatible. Users can rate forum posts in BuddyPress. Good posts are highlighted and poor posts diminished. Highlighted karma points shown for each user. Only works with forums for groups; not compatible with site wide forums.
Features & Options: 
* Post rating and responses via ajax. 
* Posts can only be rated once: thumbs up or thumbs down. This can be replaced with ‘like’ and ‘dislike’. Super-admins can rate a post as much as they want, however group admins can only rate once. 
* Good posts are highlighted light yellow (default +10), great posts are highlighted bright yellow (default +25), poor posts become slightly opaque (default -3), and very poor posts have their content hidden and viewable via an ajax link. (default -6). 
* Karma points are given to each user based on their posting history. Karma points can be based on total accumulated ratings (good for quiet sites), average post rating (good for very busy sites) or a balance of the two (good for medium traffic sites). The default is the later. 
* User Karma points are highlighted depending on number of karma points. There are 5 levels (based on natural log). Default, above 7p, above 19p, above 51p, and above 138p. The scale goes from grey to bright yellow. These values can be edited in bp-rate-forum-posts.php 
* Topic ratings are shown in group and forum listings view using the rating of the initial post. 
* Only logged-in users can rate posts. 
* No new database tables are created. 
* Post Karma shows on Member view 
* There is an admin screen to change karma levels, post highligting and diminishing values, and karma calculation method 
* No post rating when the topic is closed (except admin)
Thanks to Intense Debate for their thumb graphics and good layout.

BuddyPress Rate Forum Posts

Users can rate group forum posts in BuddyPress. Good posts are highlighted and poor posts diminished. Highlighted karma points shown for each user.

Rate vs BuddyPress Rate Forum Posts