I advertise my site SelectiveMobile.com using keyword ppc marketing on Google, Yahoo and MSN? Are there any other network that are as effective but less costly?
I think some people do manage to get a lot more out of 2nd and 3rd tier PPC networks by doing a lot of traffic filtering and geotargeting of their own, on top of whatever the PPC network is (or isn't) doing. One of the primary reasons people don't find the cheaper PPC networks very profitable in some cases is because you're often not able to accurately geotarget, and can end up with a ton of asian traffic, for example, hitting your english landing pages. So some people do their own targeting and filtering to avoid this situation.