1. PPV / CPV
1.1. Top Five
1.1.1. http://www.trafficvance.com
1.1.2. http://www.leadimpact.com
1.1.3. http://mediatraffic.com
1.1.4. http://adonnetwork.com
1.1.5. http://directcpv.com
1.2. 2nd Tier
1.2.1. http://clicksor.com
1.2.2. http://adoori.com
1.2.3. http://findology.com
1.2.4. http://www.jemamedia.com
1.2.5. http://ezanga.com
2. Display / Media Buys
2.1. Self-Serve
2.1.1. http://megaclick.com
2.1.2. http://mochimedia.com
2.1.3. http://sitescout.com
2.1.4. http://pulse360.com
2.1.5. http://www.google.com/displaynetwork
2.1.6. http://www.adperium.com
2.2. http://cpxinteractive.com
2.3. http://adbuyer.com
2.4. http://adengage.com
2.5. http://adblade.com
2.6. http://advertise.com
2.7. http://www.advertising.com
2.8. http://admarketplace.com
2.9. http://www.contextweb.com
2.10. http://adknowledge.com
2.11. http://admanage.com
2.12. http://casalemedia.com
2.13. http://rubiconproject.com
2.14. http://www.valueclickmedia.com
2.15. http://tribalfusion.com
2.16. http://adroll.com
2.17. http://chitika.com
2.18. http://www.traffiq.com
2.19. http://www.burstmedia.com
3. Search / PPC
3.1. The Big Three (err.. Two)
3.1.1. http://google.com/adwords
3.1.2. https://adcenter.microsoft.com
3.2. 2nd Tier
3.2.1. http://miva.com
3.2.2. http://7search.com
3.2.3. https://ads.kanoodle.com
3.2.4. http://www.looksmart.com
3.2.5. http://www.search123.uk.com
3.2.6. http://www.adbrite.com
3.2.7. http://www.bidvertiser.com
3.3. In-Text
3.3.1. http://kontera.com
3.3.2. http://infolinks.com
3.3.3. http://trafficvance.com
4. Social
4.1. http://www.facebook.com/advertising
4.2. https://ads.pof.com
4.3. https://www.myads.com
4.4. Twitter
4.4.1. http://sponsoredtweets.com
4.4.2. http://ad.ly
4.4.3. http://izea.com
4.5. App Traffic
4.5.1. http://rockyou.com
4.5.2. http://socialhour.com
4.5.3. http://www.socialmedia.com
4.5.4. http://advertiser.cubics.com
5. Mobile
5.1. Blind Networks
5.1.1. http://www.mojiva.com
5.1.2. http://inmobi.com
5.1.3. http://www.buzzcity.com
5.1.4. http://www.madvertise.de
5.1.5. http://adfonic.com
5.1.6. http://www.admob.com
5.1.7. http://www.admoda.com
5.2. Premium Blind Networks
5.2.1. http://www.greystripe.com
5.2.2. http://www.millennialmedia.com
5.2.3. http://www.jumptap.com
5.2.4. http://huntmads.com/?lang=en