PPC for publishers thru XML/JS feeds will work best if hte publisher has great traffic - and some offer PPC feeds for free.
PPC as an advertisement is great at drawing targetted traffic to your site. PPC is a very effective way given the proper treatment. Identify your niche and select the market you want to cater to and start from there. Research also on the keywords your desired market would most likely be looking for. It really all boils down to what your site offers to your traffic. Drawing in targetted traffic is just the initail phase IMO prior to conversion
