Pageviews, hits, visits and other ways
to measure web site traffic
There are many different ways to measure the popularity of your website: hits, impressions, page-views, visitors etc. Some are much more useful than others... especially when it comes to talking to potential advertisers.
A "hit" is an ill-defined measurement which is totally useless from an advertising point of view. In practical terms, one "hit" represents one file loaded from a server.
For instance, a page that contains 7 graphics along with the text will produce 8 hits every time it is viewed. Webmasters love to quote hits since they make even the smallest of sites sound big... but they don't MEAN anything. It's like trying to sell advertising space on the outside of a shopping bag on the basis of how many items a person will carry in the bag!
A page view corresponds to one "showing" of a complete page. Each page-view can generate one or more impressions, depending on how many ads are on the page.
An impression corresponds to one "showing" of a given advertisement. This is a very common measurement.
Visitors, and Unique Visitors
A visitor represents one person coming to your site. "Unique visitors" measures the number of distinct people who come to your site in a given time-frame. For example, your site could have 100,000 visitors per month but only 20,000 unique visitors per month (each person comes back 5 times on average). Many sites measure unique visitors on a 24-hour basis: any return visit within 24 hours does not count as a unique visitor, but if the same visitor comes back after 24 hours has elapsed they count as a second unique. Each visitor is likely to generate several page views (and therefore several impressions).
Circulation and Reach
The circulation of a newsletter or ezine is the number of subscribers to that publication. The reach also includes the number of people who receive a copy second-hand i.e. passed on by friends and colleagues.