itweet.net
iTweet is the best interface for using Twitter on the iPhone or the Web! Built-in autorefresh, search and hashtags. Full follow, block and notifications features. See current Twitter trends with one click. Watch conversations with inline 'in reply to' lin
nutshellmail.com
Receive all your Facebook & Twitter updates through a single email for free. Our updates also support Twitter Search, MySpace, LinkedIn, and Email Forwarding.
seesmic.com
Seesmic, the best Twitter client for Desktop, Web
and Mobile, manage multiple Twitter accounts, Facebook feeds and pages and access Twitter Lists.