CTR
CTR (Click-Through Rate) is the number of times an advertisement is clicked upon over the number of times the advertisement is served. Typical click-through rates have been declining (a click through rate of 1% would be very high). While click through rates help determine the effectiveness of the online advertisement, advertisements also contain a branding impact. The click-through rate will determine the cost of an advertising campagn that was based on PPC / CPC and CPA.