AOL launched its instant messaging and presence computer program. The instant messaging system uses the proprietary OSCAR instant messaging protocol and the TOC protocol to allow registered users to communicate in real time.
Stand-alone official AIM client software includes advertisements and is available for Microsoft Windows, Windows Mobile, Mac OS, Mac OS X, Android, iOS, BlackBerry OS. The software, maintained by AOL, Inc., at one time had the largest share of the instant messaging market in North America, especially in the United States (with 52% of the total reported as of 2006). This does not include other instant messaging software related to or developed by AOL, such as ICQ and iChat. As of June 2011, one reported market share had collapsed to 0.73%. However, this number only reflects installed IM applications, and not active users.