It's easy to ignore the ads if you know they are ads. What about sponsered content in movies, music, tv, news, etc? We have seen all of these used. The drive to promote a message to someone goes waay beyond advertising.
The difference I see is that there is feedback on the ads other than sales and it seems like you could closely tailor ads to specific demographics.
I think this is the risk we pay by reading the Internet? The filtering implicit in things going viral is a mixed bag.