Biggest directory of Ad Networks + Affiliate Programs + Traffic Traders + Media Companies
I tried to put them togheter on my website AdLinksON (more than 1500 listings) . I did not make a review of them or something like that but for each website you can have usefull statistics like alexa and google rankings , indexed pages in google and bing and other usefull stats like the whois data, site age, keywords tree....
Anyway i did not have the time to put them on categories but you can use the search function to find what your looking for. Ie:
"buy traffic" - link
"CPA" - link
Feel free to add other websites related to those fields.
I can export them here to post a big list but i'm not sure i'm allowed to post so many links