I've occasionally tried getting traffic from some of the 2nd and 3rd tier competitors to the Big 3, and haven't had much success. But there are more and more businesses attempting to compete in this market, and I think it's time to branch out to see what else there is to offer. I stumbled across one site that offers website traffic based on contextual advertising across a large network of sites. I assume there are others like this out there, but I haven't actively looked for them in a very long time. The pricing seems reasonable, so I'll be doing some experiments with as many as I can find (that look legitimate) and will report back with any results. If you have suggestions, let me know.