But there are clear hurdles that mobile search providers (from the big engines, to smaller services like Local.com and NearbyNow) and service carriers have to tackle before PPC can become the dominant mobile ad model. Combating click fraud, for example, is a top priority, as the tech that's in place for the Internet won't necessarily work for the mobile Web. Chris Silver Smith's piece is a thorough analysis of what the industry needs to consider before the mobile local search market can truly explode.