IM client Ratings

I have used many im's over the years. It is my conclusion that the only way to really improve im software is to make it truly cross compatible. Companies have tried over the years but it always seems to fail. The yahoo and live messenger partnership is good, but does not work with mobile messaging. GTalk's platform seems to be the most cross platform compatible, but it lacks the rich features that the other major im players have, ie video. I am currently using gtalk and like it mainly because of it blackberry support and small footprint. Send comment would like every ones input.