Despite its name, the specifications for the protocol are proprietary. AOL has gone to great lengths to keep competitors, namely Microsoft, Jabber, and Cerulean Studios, from implementing compatible clients for their proprietary messaging system. In 2002, AOL signed a contract with Apple, Inc., allowing them to use it (as well as AOL's own code libraries) in their iChat application. This allows iChat users to interact with ICQ and AIM users directly. As a part of this deal, Apple's .Mac/MobileMe service could hook into the service by allowing members to log in using their .Mac/MobileMe accounts (in the form of the full e-mail address — username@mac.com) on the AIM network.
Large parts of the protocol are nowadays understood after reverse-engineering the protocol, implemented by an ever-increasing number of 3rd party clients.
On March 6, 2006, AOL released the AIM SDK and launched a developer website, allowing developers to build plugins for AIM Triton, and build their own custom clients, which connect over the OSCAR protocol. They had not, at that point, however, released any information about the protocol itself.
As of June 16, 2007 an underground programming group Uground Productions had been working on a full fledged OSCAR server.citation needed At that time, the server was in the testing stages and had Instant Messaging and Other Services implemented.
On March 5, 2008 AOL released the OSCAR protocol documentation. Google also provides the ability to sign into AIM network via the GTalk client built into GMail.
