AIM, Yahoo, and MSN (not sure about ICQ) are all closed protocals. E.g. the companies behind them (AIM, Yahoo, and Microsoft) don't support any client besides their own. Any client you use that uses their protocals (Pidgin for example) isn't officially supported or recognized by them. Thus when AIM, Yahoo, or MSN changes something you sometimes get breaks in Pidgin and have to wait till the developers of Pidgin find a workaround or whatever

Hence why Nokia is not bothering to offer this by default (answer to romanianusa) and hence why we have to go through something like Haze instead of having out of the box support.