Instant Messaging

Unofficial desktop client for Facebook chat

A traditional chat with group videoconferencing

Share files and chat with friends safely

iOS's iMessage now also on Mac OS

A single program for all your IM accounts

Cooperative whiteboard and voice communication through Jabber

AOL's instant messaging program

Chat with friends on this multiplatform messaging client

Just like Whatsapp but from your Mac's desktop

Multiplatform IM client