To be honest, I haven’t used any instant messaging system much since college. But every once in a while I fire up Gaim just to see if anyone I know is on AIM or ICQ. I have a Yahoo account, but I’m not sure anyone I know actually uses Yahoo Messenger, and I’ve been avoiding MSN mainly on principle.
This time it’s Yahoo that’s blocked other clients from connecting to their networks. The most high-profile victim has been Trillian, another client which talks to multiple IM networks, but of course Gaim was hit as well. What’s interesting, this time, is that Yahoo claims it’s doing this to cut down on spam.
Now let’s think about this: In order to send and receive instant messages on Yahoo’s network, you need a Yahoo account, correct? So no matter what software a spammer uses to connect, he still needs to log in, which means Yahoo can control them inside the network. This is where current IM systems are fundamentally different from email: instead of many independently-controlled systems talking to each other, each IM service is one system with many accounts, more like a website with required registration. Place limits on what clients can do, and (barring bugs in your server) no matter what client someone uses, he can’t get around your spam/virus/hack controls.