Time to Abandon AIM
AIM and Yahoo! were the predominant protocols for IM when I started using Linux, and for a very long time they were the only reliable ways to chat with most of my friends and family that used Windows or Macs. IRC was fine if I wanted to chat with other Linux folks, but most of my contacts didn't use IRC and weren't about to switch or pick up yet another client because I was the odd man out on the desktop.
Pidgin, formerly Gaim, made it possible to chat on these networks. AOL and Yahoo! have offered (and may still do) proprietary clients for Linux, but they've been updated infrequently and tend to be less reliable than their open source counterparts. Most of the time the Pidgin/Gaim team has been able to work around periods where AOL or Yahoo! have changed protocols and accidentally or deliberately blocked third-party clients from the network.
As Doliner points out, the Open AIM program was a breath of fresh air. AOL provided documentation, developer kits, and developer application keys to connect with the network. Now AOL has shut it all down, and has stopped issuing new keys. The Pidgin project is faced with going back to the bad old days of reverse engineering the protocols and hoping they can keep up if and when AOL decides to make changes.
Maybe the better option is to drop support for AIM and ICQ entirely if AOL starts moving away from the existing protocol. We have Jabber now, an open protocol that's supported by Google Talk, Facebook, and plenty of open Jabber servers for folks who don't like having to sign up with one of the big players. It's even possible to run your own Jabber server if you're so inclined. I can chat with people on Google Talk from a Jabber.org address, and use virtually any IM client that supports XMPP/Jabber without a specific blessing from Google, Jabber, or Facebook.
The ranks of AIM loyalists are dwindling, so maybe it's time to start working on moving our friends and family to more open networks if AOL doesn't want to support open development. I've always liked the fact that Pidgin supports such a wide range of protocols, but maybe it's better to focus on Jabber at this point.