When Twitter announced it's new Twitter API changes it left many the disgruntled third party app developer who had built tools and services on top of the API. Where many have been forced to simply work around these changes regardless of the damage caused, others will be forced to abruptly shut down. Unfortunately, the latter is true for Twimbow.
There are many tools to analyze and rank Twitter users, but a new one takes a trick from Google's book. Trst.me uses an algorithm similar to Google's PageRank to give any Twitter user a score from one to 10 based on their followers' networks of followers.