It seems that programs these days are confused about what the button with the big
X means. When I push close, I expect the app to close. I don't mean
minimize, I don't mean pretend to close and drop into a
tray icon, I mean
close.
Apparently in win32 the application recieves the window close message and can act on it in any manner it chooses. Napster, Scour Exchange and AIM all interpert it as meaning 'hide.' Napster and Scour Exchange are guilty for obvious reasons, as they want you to assume they are closed while they continue to serve files, wasting bandwith while providing them with more content to attract new users. I can immagine this being a big problem on college campuses where computers are often left on all the time and people may assume Napster is closed.
AOL has no reasonably explainable reason for keeping AIM running when you're not online, but its a part of this trend of apps that don't close unless you take the effort to kill them. Usually closing involves right clicking their tray icon and choosing close, but a more sadistic application may require a ctrl+alt+del or worse.