Of course, iChat does pack in one massive advantage over Adium: excellent audio and video chat support. In Lion, iChat supports full-screen mode when you're video chatting, which works great. If you swipe away from the full-screen video chat to another screen on your Mac, the call continues. (That's in contrast to FaceTime's full-screen mode, which places your call on hold.) I find iChat's video calling often works quite well. In my experience, sometimes I can get better call quality with iChat, and sometimes things are better in Skype. iChat has long made video conferencing (and screen sharing) ridiculously simple, and that continue in Lion. You can even use to the new silly Photo Booth effects as you video chat, if you're into that sort of thing.

late in Snow Leopard's tenure. Back when the desktop edition of Apple's iPhone and iPad video conferencing technology was introduced, some of us wondered whether the FaceTime app would one day merge with iChat. The answer from Apple has thus far been a resounding "no." Lion's incarnation of FaceTime--version 1.1--doesn't differ much from the Mac App Store version of the video-conferencing tool for Snow Leopard. In fact, the only notable change between the version in the Mac App Store and the version included with Lion is the introduction of support for Lion's full-screen mode while video chatting.

FaceTime and iChat are two different beasts. FaceTime still only works for video chatting; you can't use the software for sending instant messages or audio chatting. And FaceTime--unlike iChat--lacks any notion of "online now": You can't know if your contact is available until you try to place the call. On the plus side, FaceTime lets you place calls not just to other Mac users with the software installed, but also to late-model iOS device users as well.