Is the number of unique IP addresses/hostnames that made requests to the server. Care should be taken when using this metric for anything other than that. Many users can appear to come from a single site, and they can also appear to come from many IP addresses so it should be used simply as a rough gauge as to the number of visitors to your server.

Occur when some remote site makes a request for a page on your server for the first time. As long as the same site keeps making requests within a given timeout period, they will all be considered part of the same Visit. If the site makes a request to your server, and the length of time since the last request is greater than the specified timeout period (default is 30 minutes), a new Visit is started and counted, and the sequence repeats. Since only pages will trigger a visit, remotes sites that link to graphic and other non- page URLs will not be counted in the visit totals, reducing the number of false visits.

A Site is a remote machine that makes requests to your server, and is based on the remote machines IP Address/Hostname.