I haven't had problems with ads. There are a few banners that rotate between vendor sites but they're all related to the hobby and sometimes they even have coupons!
I'm not sure what everyone is talking about with all of these ads?!
Also... Domain registry, hosting, bandwidth etc all cost money. I can't put a price on all of the of the technical info, resources and access to plants I can't buy in my area!!!! So I would have to say its a pretty fair trade.