The adult industry use to be good at this approach, but not anymore.
http://en.wikipedia.org/wiki/Native_advertising
Native advertising is an online advertising method in which the advertiser attempts to gain attention by providing content in the context of the user's experience. Native ad formats match both the form and function of the user experience in which it is placed. The advertiser's intent is to make the paid advertising feel less intrusive and thus increase the likelihood users will click on it.