YubNub

YubNub is a networking web service with a command line–style interface.

Greasemonkey

Customize the way a web page displays or behaves, by using small bits of JavaScript.

Send group messages to people at places

Your Bookmarklets, On Steroids

Shortmarks is like an enhanced speed dial for web browsing.

Short-range anonymous messaging (Secret meets Firechat)

Listen to your news stories, narrated by humans