If you are lucky enough to have found a well converting pay per click to affiliate offer, you are probably looking to expand the reach of that offer. Obviously the big 3 PPC engines: Google Adwords, Yahoo Search Marketing, and MSN Adcenter make up the bulk of all PPC traffic. But if you stopped there, you may be leaving money and clicks on the table. To capture all the possible PPC traffic for your niche, also consider 2nd tier PPC networks. Oh sure, we have all heard random people in a forum or blog saying that 2nd tier networks are garbage and to stay far away from them. But never believe what you hear about any pay per click service until you test it for yourself. What might have failed miserably for someone else could turn out to be a gold mine for your particular campaign and offer.