Twtrland is a new service that converts Twitter streams into detailed profiles to try and make it easier to decide whom to follow.
Simply plug in the Twitter handle you want to analyze, and Twtrland will build a profile for you. (See mine above.) The profile includes info like how often the user is retweeted, how many times she or he tweets per day, a breakdown of tweet content (plain tweets, pictures, @replies, etc.), most-retweeted tweets (Famous Words), top followers and a sampling of tweets.
According to the service's site, one of the main problems Twtrland is trying to solve is: "Deciding if someone is follow-worthy. These are not your real life friends, but people that are supposed to interest you. Hard to decide based on last 10-15 tweets, avatar and description. We go deep in his history, and sum it all up to the simplest profile we could think of to help you decide in a glimpse. to follow or not to follow."