If someone wins, someone else has to loose: the consideration is rather obvious. This is what is happening in the online advertising industry, where Google and Yahoo are experiencing an extraordinary revenue growth "stealing" the adverting money from the potential revenue of traditional media companies.
An article on Informationweek reports the two giants are "diverting advertising revenue established information companies."
This is basically the result of an evolution in the market: advertisers look for alternative ways of promotion and search engine and contextual advertising prove to be rather efficient and cost-effective. Unfortunately (as readers) we already know what is going to happen if information site won't get enough money from advertising: they will start charging for the content (and the NYT is about to launch subscription based articles).