On Wikia, you can give ratings on articles
The page rating is included in the footer area of any article in a content namespace, (on the Monaco skin). On this you can see the current rating, and by hovering over it, rate it yourself. The top voted articles will appear on the "Top Voted" widget.
You can choose between one and five star ratings, and once rated, you can remove your rating ("Unrate it"). This is then added into the average of all other ratings which is then graphically displayed (this is unlikely be an integer, and will often show up as parts of stars).
These ratings can be also accessed via the API, via query list module with the name of
wkvoteart. Take a look at http://www.wikia.com/api.php, and search for 'Get most rating articles'. Such as http://help.wikia.com/api.php?action=query&list=wkvoteart