click-through rate - technical definition

The number of times a link on a Web page is clicked compared to the number of times it is displayed. Advertising royalties paid to Web sites are often based on click-through rate (CTR), and the amount paid per click-through is considerably higher than the cost of an ad that is displayed without accounting for its effectiveness.

The click-through rate is also used for other than advertisements. For example, it can measure how many times people click a link to go to another part of the Web site. See pay-per-click, banner ad, conversion rate and CPM.