A hit occurs when a file is loaded from a web server. Several hits will occur when a web page is loaded – e.g. one hit for each image on the page and one hit for the page itself. In common usage, however, people are referring to visits when they use the term hit.

/

A visit occurs when someone loads a web page from your server thus “visiting” your site. The number of hits will always be equal to or greater than the number of visits.

/

Normally used to refer to a single display of a banner ad. For example, 1,000 impressions of a banner imply that the banner was seen 1,000 times. Some traffic services use the term impression to refer to a visit.

/

An abbreviation for Cost Per Thousand. Prices for traffic are often quoted as “$X CPM” - for example, $2 CPM indicates a price of $2 per thousand. (Note: it is not correct to say “$X per CPM”).

/

Short for cost per click. Often used in banner advertising to sell or buy banner clicks. For example $0.15 CPC means 15 cents per click.

1,000 visits could be achieved by having one person load a page 1,000 times or by having 1,000 people load a page one time. If visits are unique, a single user is counted only once in a certain period of time. Usually, a level of uniqueness is specified such as: “X hour unique” – that is, the same user is only counted once every X hours. Most commonly, traffic is 6, 12 or 24 hour unique. Usually, a user is identified by his/her IP address, which is unique to every computer on the Internet. In some cases, the determination of whether a hit is unique depends on the server’s ability to store a small identifying file on a visitor’s computer (a “cookie”).

Refers to traffic with no specified level of uniqueness. The same user could be counted several times is he/she reloads the campaign page. On average, raw traffic is 50-75% unique.