Online advertising expert David Szetela is owner and CEO of Clix Marketing, one of the few agencies that specializes exclusively in pay-per-click (PPC) advertising. His PPC articles have been published in MediaPost, Search Engine Watch, Search Engine Land, MarketingSherpa, and on his company's blog (www.clixmarketing.com/blog). He is the Principal PPC Editor of the paper and online publication SEMJ.org and the PPC expert faculty member for the online certification company Market Motive. He is also a frequent speaker at such industry events as Search Engine Strategies, SMX, PPC Summit, and ad:tech. He also hosts a weekly radio show called PPC Rockstars that is distributed by Webmasterradio.fm and iTunes. Joseph Kerschbaum has optimized thousands of PPC campaigns and is Director of Client Services at Clix Marketing. He has written hundreds of articles on paid search advertising for numerous industry blogs, and he is a regular contributor to Website Magazine and Search Engine Land.