CPCRather than paying a flat rate to run an
ad on a site, sometimes advertisers will pay only for the number of
clickthroughs, or cost-per-click (CPC), they derive from the ad. While it's popular with advertisers, CPC payment is frowned upon by most Web sites and by the IAB.
After all, banners serve a larger purpose than just getting people to click. Like advertising in other media, banners help raise general brand awareness and familiarity with a product. While only 1 to 2 percent of users actually click on banner ads, a much larger percentage will gain an overall familiarity with the product or brand. CPC buys ignore this value altogether, giving advertisers a mighty good deal.