I also think it is somewhat unfair. They have lot of money from their ads, so they can create product in another category (for example GPS), and offer it for free, while other companies who don't have those advertising dollars can't offer their product for free. Basically they can easily kill competition in certain niches, since they can support their product by money gained by another product (Adsense/Adwords). Maybe it is not unlawful, but fair is it not.