Am I bothered by the Google ads at Ancestry.com? Not really.
I pay to watch a movie in a theatre, but there are ads before the movie. And in some movies if I watch closely, the people all drink one brand of pop. Any vending machines that happen to be shown in the background are for that same brand. That's not an accident either.
Frankly, the ads are just about like my "gmail" page where I pretty much ignore those as well.