The instant messaging world became just a little more open on Wednesday when AOL released Open AIM 2.0. Some of the requirements attached to the release might still turn off open source developers, though.
The first release of Open AIM was in 2006, but that release was missing some vital documentation -- specifically, for the core protocols that work with the AIM backend. Now, theoretically, developers can write libraries/clients that authenticate and communicate just like AOL's official client without having to decipher the protocol first.
Of course, the hard lifting there has already been done by the Pidgin (formerly Gaim) project which provides libpurple -- a library that handles the actual connections to various instant messaging services (including, but not limited to, AIM). The libpurple library is used by Pidgin (a multi-protocol IM client for Linux and Windows) and Adium (a multi-protocol IM client for Mac OS X).
Even if the Pidgin project hadn't already deciphered the AIM protocols, AOL's restrictions might be a bit of a turnoff -- specifically the license requirement that "if your application exceeds 100,000 peak simultaneous users, you must implement Advertising" as one of two mandatory features. It's hard to say whether Pidgin ever hits 100,000 simultaneous users -- Pidgin probably has at least 100,000 users, but 100,000 at a time? Maybe not.
At any rate, this restriction isn't compatible with open source licenses -- you can't dictate through an open source license what features will or won't be implemented. The GNU General Public License (GPL) doesn't allow this, nor do any licenses that pass muster with the Open Source Definition.
So AOL has taken another tentative step towards openness -- but still falls short of actually meeting open source developers on their own terms.
Joe 'Zonker' Brockmeier works for Novell as the openSUSE Community Manager.