Top rated in Instant Messaging & VoIP
iMessage lets you send messages to anyone on a Mac, or an iPhone, iPad...
Send instant messages, share files, and hold video conferences.
Send messages, have group chats, and share pictures using the Whatsapp services.
A desktop messenger that allows using the services of Telegram.
Do more than just IM with Yahoo!
Free-to-use voice and text chat application for gamers.
A chat-based workspace in Office 365 with private group conversations.
Popular and, probably, the best instant messaging client for you Mac.
Send messages, make video calls and stay connected with your friends.
Send messages, exchange files, and make voice and video calls.
Communicate with all of your friends personally and in group chats on your Mac just as you would with your mobile device.
Video chat/calling tool; see up to 6 friends at once.
QQ connects you to over 600 million Chinese QQ members and many of your favorite websites and useful tools.
VoIP program which allows you to make phone calls over the internet.
Integrated functionality for instant messaging, presence, conferencing and voice.
Stay in touch with your colleagues and monitor conversations.
Powerful and efficient instant messaging client.
Spark is an open source, cross-platform instant messaging client for businesses.
iGlasses allows you to adjust and manipulate your webcam's video settings.
Traditionally, chat clients on the Mac have been anything but glamorous.
Google, Skype, Yahoo, MSN, AIM, Jabber, Facebook, SMS, Fax...
Supports private and group communication as well as file exchanges.
Connects to the Calendar app and monitors your Zoom meetings in real time.
Freeware Mac OS X IRC client created by Steve Green.