Free
AdiumBook
Sync Adium and Address Book
Free
Sync Adium and Address Book
Free
ooVoo: Free Multiple Video Chat Client
Free
net4mac: Social Networking for Mac Users
Free
New Emoticons for MSN Messenger
Free
Mac Messenger: Open Source MSN Messenger Client for Mac
Trial version
iSpQ VideoChat: Meet Other Video Chat Users from Around the World
Free
Jitsi: Free Messenger Client Supporting Audio and Video Chats
Free
Scalaris: An Elegant and Discreet Twitter Client with Growl Support
Trial version
Snak: An IRC Client for Professionals
Trial version
Easy local network communication
Free
Full featured IM client for internal communication
Free
Use Skype remotely
Free
56 Free Effects for iChat
Paid
FaceTime: Video Chat Done the Apple Way
Paid
Tweetbot for Twitter: A Full Version Program for Mac
Free
goober Messenger: Multi-functional messenger with TV, radio and more
Free
An alternative to Skype
Trial version
Video effects within iChat
Trial version
Index all your chats in a snap
Free
Night Owl: A Free Social & Messaging Program for Mac
Free
InstaMaster: Upload photos & videos for Instagram
Free
Janetter: A Twitter Client for Mac
Free
A free program for Mac, by PSI.
Free
Social Lite: A Free Program for Mac