Originally Posted by Dynamix
I guess but will they make money from making a free to use IM program? I guess they may gain publicity and then more ppl would buy adsence and stuff
Exactly - more publicity means more hits to google.com, more buyers of adsense, and also more companies wanting to pay to get at the top of searches.
Take MSN too - they obviously get payed by companies to place their adverts on MSN Messenger, such as Ebay. Also the adverts under your buddy list must get millions of views each day. If Google did the same, they'd get money from that too.