Many may have already heard of AideRSS, a tool which allows users to filter their RSS feeds to receive only those deemed most popular based on several criteria. The engine behind AideRSS, called PostRank is now available as an API with unlimited potential applications.
To put it simply PostRank measures the popularity of RSS feeds, blog posts, articles and news stories by taking into account such factors as the number of times it’s been: Tweeted, saved to del.icio.us, Dugg, commented on, and been linked to. Basically PostRank can be used by anyone looking to gauge the buzz surrounding any new posting on the web who doesn’t want to rely on only one source to measure it.
Postrank.com In Their Own Words
“PostRank is a scoring system developed by AideRSS to rank online content, such as RSS feed items, blog posts, articles, or news stories. This scoring system is based on social engagement, which refers to how interesting or relevant people have found an item or category to be.”
Why Postrank.com It Might Be A Killer
This is an excellent idea and the potential applications for this API span the gamut of web 2.0 applications since it allows multiple sources to be compared to come up with a true measure of the popularity of an item.
Some Questions About Postrank.com
How does PostRank generate revenue from this service? They are offering the API code for free, so will they be somehow monetizing from the data that goes through it? 
