That's my point precisely - Adium doesn't do anything that Pidgin cannot, but the UI between the two apps is worlds apart. IMHO it's the classic example of the failing of open source - too much functionality, no way for the layman to get to them.
Except the shiny icons and Aqua, i don't see much difference in UI between Pidgin and Adium. Correct me if i'm wrong but from what i see, Adium is just Pidgin "localized" for Mac.
