If I have to say there's one flaw with Yahoo Messenger for the Mac, it's the file transfer system. Oh, you sending a file works well. The issue is actually getting a file. I had someone tell me to accept the file transfer and I never seen anything telling me they were sending me anything. I think that's one little flaw Yahoo could fix if they quit focusing on the other versions.
I know I said one flaw but I'd like to see this added in the Mac version: Photo Sharing.
It would be nice to have the comfort of a Windows version in the Mac version without having to open VMWare Fusion.
