You guys should add Gwibber to the list
It's for Linux and is available from the repositories
It's compatible with a lot of different network such as twitter, Friend Feed and whole lot more
It deserves to be on the list

EchoFon: (Formally TwitterFox, Firefox Add-On for Twitter)
http://echofon.com/

Twitterific (mac only)
Blu (windows only)
Ada
DestroyTwitter
MadTwitter
Seesmic
Spaz
Textwit
Twibble


i found these through http://www.nunokaka85.co.cc/

Links?

all of the links for them are right on that website.

Yoono.com is a Firefox browser social client (it can also be considered as a chatting client since it does it as well).