Ad Clicks
Action from a user clicking on an advertisement to get more information.

Ad Views
Display of an advertisement on the HTML page a user is viewing.

Click through rate
Percentage of users who click on a viewed advertisement. This is a good indication of the effectiveness of this ad.

Hit
An action on the Web site, such as when a user views a page or downloads a file.

Page Views
Also called Page Impressions. Hit to HTML pages only (access to non-HTML documents are not counted).

User Session
A session of activity (all hits) for one visitor to a Web site. A unique user is determined by the IP address or domain name. By default, a user session is terminated when a user falls inactive for more than 30 minutes. Synonym: Visit.

Views
See "Page Views".

Visit
See "User Session".