Jeff Key wants to end default buttons on Focus-Stealing Dialogs but I think the problem is bigger than that. I don't think ANYTHING should be able to steal my focus while typing. I have ranted about this before both in places where it could help (emails with MS employees) and in places where it can't (certain blogs). Not only is it annoying to suddenly find myself typing in a IM conversation with someone on AOL when less than half a word ago I was typing an invoice for a client, it is DANGEROUS for programs to be able to steal focus like this.
Here is a classic example that happens more than you might think: Johnny is surfing and chatting with friends via MSN Messenger (insert any other task here) and typing away as fast as his 2-fingers will carry him. While in the middle of typing "silly", he suddenly hears the "dink" sound that happens when you try to do something that a dialog doesn't want you to do. It "dinks" twice on the 2 L's and then, as his finger hits the "y" key and he looks up, the cause of the problem is gone. He shrugs and continues typing, filling in the missing "lly" and forgetting the whole situation. Unfortunately, the search toolbar he just installed accidentally comes with a very nice trojan horse that pops up new IE windows every time he gets online. He doesn't remember installing anything but, for some reason, I won't believe him when he says that. "sure, you didn't" I say as I help him uninstall the triple-digit leagon of spyware now running in the background.
There is no reason that a program should be able to steal my focus. When I Outlook, I don't sit slack-jawed waiting for it to open, I go back to whatever I was doing, Outlook should open behind my current window. If it must, then it can pop up in my way visually, but if I am typing then I STILL want to be typing wherever I was, not wherever the latest window popped up, be it Outlook, IE, AIM, or anything. There are NO circumstances where this is acceptable or preferable.