Tribalfusion is one of the few companies that thrive on CPM, that is Cost per Thousand, advertising campaigns which is not that hard to get into. It actually took only two weeks until I got accepted and could run a cpm banner campaign here on ghacks. The advantage of CPM ads is of course that you do not need to think much about ad placement and layout unlike CPC, that is cash per click, ads like Google Adsense or Yahoo Publisher Network. You do get paid a fix amount of money depending on the type of banner ads that are displayed on your website. The range usually is between $0.50 up to about $2 per 1000 impressions on your website which can sum up nicely if you have lots of traffic.