Allen Stern points out that RSS filtering service AideRSS has added Twitter to its PostRank algorithm. AideRSS works by measuring social media interaction with blog posts, and then comparing them to what's normal for that blog. The service then algorithmically applies a ranking to each post allowing users to filter out only the best posts based on the theory that people will only bother interacting with the most interesting or worthwhile content.

We're huge fans of AideRSS at ReadWriteWeb. Not only have we written about them a lot, we've also used AideRSS to filter aggregate feeds for the top content for a number of our toolkit posts. Adding Twitter support is an interesting move because it confirms Twitter's growing influence in the social media space, and lets blog owners see how their content is being spread across the microblog service.

Since we published our first look at AideRSS last July, their PostRank algorithm has changed a lot. At launch, PostRank included information from comments, Digg,, Technorati, IceRocket, and Bloglines -- now the latter three have been replaced with Twitter links and Google blog search conversations. Some of those changes likely had to do with API restrictions, some likely with just general tweaking to make the algorithm perform better.

Because AideRSS calculates PostRank against only that blog's past performance, the ranking is a fair representation of that blog's best work. For example, a PR 10 post on ReadWriteWeb would require different interaction metrics than a post on a small personal blog. PostRank would be easy to cheat -- you could comment a million times on your post, get your friends to Digg it, tweet it, add it it -- but since the service isn't measuring you against other blogs, there's really no incentive to cheat it.

AideRSS also announced support for OpenID.