This is the second time this has happened...first time was in Panther, this time in Tiger, so I know it's not the operating system at fault. I have a friend who has always shown up in my iChat buddy list, but then randomly disappears. I check another screen name and he's online. I ask him if he's blocked me, and he says no. This happened earlier this year and I actually checked the person's computer over to make sure, and he was right. I don't want to have to make another screen name! What is going on???