Download Tweetie 2.1 from the App Store now – supports Lists and Reweets

Gangs in New York talk Twitter: Use tweets to trash-talk rivals, plan fights – Just as they probably use cell phones, too. Even bad guys have access to open communications tools.

Bit.ly Partners with Security Firms to Block Spams, Scams from Twitter – The URL shortener will work with Sophos, Verisign and Websense.

Square: Twitter Co-Founder Launches New Mobile Payment System – Jack Dorsey’s new company uses iPhones to read your credit card for payment.