What is paid search advertising and why is it increasing in popularity?

What will be an ideal response?

Thirty-five percent of all searches are reportedly for products or services. Marketers bid in a continuous auction on search terms that serve as a proxy for the consumer's product or consumption interests. When a consumer searches for any of the words with Google, Yahoo!, or Bing, the marketer's ad may appear above or next to the results, depending on the amount the company bids and an algorithm the search engines use to determine an ad's relevance to a particular search.Advertisers pay only if people click on the links, but marketers believe consumers who have already expressed interest by engaging in search are prime prospects. Average click-through in terms of the percentage of consumers who click on a link is about 2 percent, much more than for comparable online display ads, which range from 0.08 for standard banner ads with graphics and images to 0.14 for rich media (expandable banners) ads that incorporate audio and/or video.