Bitly Partners with Security Firms to Block Spammers

Bit.ly, the service Twitter uses to shorten URLs to keep them under the services 140-character limit, announced partnerships on Monday with Verisign, Websense and Sophos that are designed to keep spam and malicious software off of the network.

Source:
http://www.wired.com/epicenter/2009/11/bitly-partners-with-security-firms-to-block-spams-scams-from-twitter/