As described on the FAQ page
http://umd.net/faq How do the ratings work?
The site-wide ratings system was designed to gauge community consensus about the value of everything that can be added by a user. You can rate photos, videos, forum posts, sites, and even site reviews. The system was built to be fair. You have to be logged in to vote, and you can only vote on each item once. It is a rolling ratings system, meaning only the latest X number of votes (currently 100) of any type, for any given item are considered, and older ones are forgotten. This allows an item's rating to change over time. For example, a site that used to be great and had high ratings may stop updating and start getting lower ratings, causing the old high ratings to eventually drop off the end. Or vice versa. Every item's rating is an average of the number of stars users gave it, which gives a level playing field for all items old and new.
We also have a separate scoring system which takes each item's user-rating and weighs it against how old that item is. Every day that passes, any item's score is weighed 1/30th less. When it's new, its score has 100% of its weight but after half a month its score is only worth half as much. Items over 30 days old are not considered at all. We use these date-weighted scores to determine the "top items" in any category such as hottest photos and forum threads, and even wammer of the day. So whatever is new, highly-rated, or both, will likely make the hot list in its section. The scores are also weighted by other factors such as the number of unique views the items have gotten, and any negative reports users have submitted on them. These scores are just relative, numerical indexes that we use internally, so they are not shown to the public. Remember that these scores are independent of and do not affect the star-ratings.
You cannot rate other users. However the site uses an algorithm that takes into account everything each user posts around the site. The user with the most highly-rated stuff, the most stuff, and the most recent stuff, gets pushed higher in the rankings. So the more you participate, and the better-rated all your stuff is, the higher your score gets. You might even become Wammer of the Day!
We have a backend that can see, globally, who is rating what. Anyone caught abusing or spamming the system will have all of his ratings removed, and will be banned from the ratings system.
The backend to this system is very complex and I will be tweaking it from time to time. So please don't take it too seriously. It's just meant to be fun and to encourage people to post great stuff.
I hope this helps to alleviate some of the confusion.
mid
Posers go away and stop wasting everyones time.
