Chat & IM

Yahoo! Messenger
messenger(Free)
Download
Free Mac Program: Yahoo! Messenger
QQ for Mac
Tencent(Free)
Download
Complete IM client with cute design and great features
Yahoo! Messenger
Michael Mateas and Andrew Stern(Free)
Download
Yahoo! Messenger
Messages
apple(Free)
Download
Apple's Messages: A Seamless Chat Client for Mac Users
Jitsi Meet
Jitsi(Free)
Download
Jitsi Meet - Smart and Powerful Computer Software For Collaborating Across Distances
Express Talk
NCH Software(Free)
Download
Virtual Telephone Compatible with Most VOIP Services
InstaMaster: Upload photos & videos for Instagram
Chengyu Huang(Free)
Download
InstaMaster: Upload photos & videos for Instagram
Chat Transcript Manager
Unsanity(Trial version)
Download
Index all your chats in a snap
Spyder
Michael Link(Trial version)
Download
Spyder: Social Network Browser
Snak
Snak(Trial version)
Download
Snak: IRC client for professionals