Mac Apps for Communications
Top 3 Communications Apps for Mac
More Communications Apps for Mac

Discord
FreeObtain power to create your own place to belong and share it with explicit soulmates you invite.
MacProteus
Freeinstant messaging client for most major IM services
Mac
Skype
FreeStay within the reach with free Skype-to-Skype video/audio calls, videoconferencing, smart messaging, and screen sharing.
Mac
AOL Desktop for Mac
FreeAll-in-one AOL client with integrated mail, AIM, browser.
MacX (Twitter)
FreeMac
Colloquy
Trial versionQuality IRC & SILC client with style.
MacZoom Meetings
FreeHigh-Quality Video Conferencing with Zoom Meetings
Mac
Telegram
FreeChat in private and group chats, share photos and videos and stay connected with everyone at once.
MacWeChat
FreeMacTextNow - Free Text
FreeMacAsterisk
FreeTurn Mac OS X into a PBX and VoIP telephony server.
MacApple Messages
FreeDownload Messages Beta and get a taste of what's coming in OS X Mountain Lion. When you install Messages, it replaces iChat. But iChat services will continue to work.
MacIP Reporter (OS X)
Trial versionFind and display your current IP number.
MacNetSpeedometer
FreeMonitor and display your Internet connection speed in form of a graphic.
Mac
Mail Designer 365
Trial versionCreate HTML e-mails and newsletters without any HTML coding.
MacKiwi for Gmail
FreeAccess each application, open new documents, and get back to recent documents with a single click.
MacEvoCam
Trial versionStream live video to websites.
MacSpamSieve
Trial versionBayesian spam filter for most email clients.
Mac
Apple FaceTime
PaidMake video calls to iPhone 4, the new iPod touch, or another Mac.
Mac
TorChat
FreeChat in anonymous rooms without getting located.
MacZoom
FreeStart or join a 100-person meeting with face-to-face video, high quality screen sharing, and instant messaging.
MacWebPeek
Trial versionTake screenshots on your Mac remotely via any Web browser.
Mac
Sky Mac
FreeMake business calls and chat with your partners easily.
Mac
iGlasses
Trial versionControl camera settings from iChat, Skype and other apps.
Mac