Free
AIM for Mac
AIM for Mac: A Classic Instant Messaging Client
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X (Twitter): A Free Messaging App for Mac
A full version program for mac
Weet: Free Instant Messaging for Mac
A full version program for mac, by The Iconfactory
One-click calling and answering
AIM for Mac: A Classic Instant Messaging Client
Talk without limits
Feature-Rich Chat Application for Mac Users