It supported instant text messaging over XMPP/Jingle or OSCAR (AIM) protocol, audio and video calling, and screen-sharing capabilities.

iChat incorporated Apple's Aqua interface and used speech bubbles and pictures to personify the online chatting experience.

With iChat, green (available), yellow (idle), and red (away) icons could be displayed next to the name of each connected user on the buddy list.

It added video and audio conferencing capabilities based on the industry-standard Session Initiation Protocol (SIP).

In June 2004, Steve Jobs announced that the next version of iChat AV would be included with Mac OS X 10.4. iChat AV 3 provided additional support to allow up to four people in a single video conference and ten people in an audio conference.

[5] In October 2005, iChat received support for encrypted communications, but only for paid subscribers of .Mac (later MobileMe and currently iCloud) service.

iChat Theater allowed users to share any file supported by Quick Look, including photos, Keynote presentations, and movies, over a video chat session.

Screen Sharing allowed two users of Mac OS X Leopard to have control of the same desktop and work collaboratively.