Pay per Click (PPC) refers directly to those advertisements that accompany Search Engine Result Pages (SERPs) generally along the right hand side as well at the top of the organic results. In Google the ones just above the organic results are currently shaded in yellow. There are really only two metrics that matter when it comes to PPC (1) CTR (Click through Rate) and (2) Conversion Rate. Click through Rate is simply the number of times a paid ad is...