Im not a huge buyer there but every now and then i try something out. Some sites work, others dont. And sadly enough every time something works it slowly dies out (depending mainly i think how many galleries you have for that specific site). But thats normal i guess. So you simply cancel that caimpaign and try something new.
Anyway what im trying to say is in general its a very good way to make some easy money without too much work if you know what youre doing. I dont recommend it to a noob but if you know a bit about sites and niches and stuff its highly worth checking it out.
Now im lazy and i just add galleries and general keywords but you can actually add keywords per gallery. So if a gallery has content of a blonde chick you can add "blonde" just for that gallery so you get very targeted traffic.
This is my last campaign i started on the 7th of this month:
Spent $121.13 and made 1:54 9 $450.00 (2nd page ratios, first page is roughly 1:250)
www.askjolene.com