This is a collection of web sites and articles I have found on the subject of Twitter analytics. I’ll post new ones to the top, so the list is in reverse chronological order, newest first.
BotOrNot — a tool from the University of Indiana to tell if an account is a bot.
Audiense — a neat, free analytics application for Twitter users.
Fernanda Viégas and Martin Wattenberg — not a web site on analytics, per se, but on visualization, which is an important part of presenting data from analytics.