What does all this mean? – hits and visits and sites and pages...
Hits represent the total number of requests made to your site during the given time period. Hits were once an often-used statistic, but are really misleading. Visits tells you a lot more about your site’s performance.
Files represent the total number of hits (requests) that actually resulted in something being sent back to the user. Not all hits will send data, such as 404-Not Found requests and requests for pages that are already in the browser's cache.
Tip: By looking at the difference between hits and files, you can get a rough indication of repeat visitors, as the greater the difference between the two, the more people are requesting pages they already have cached (have viewed already).
Sites is the number of unique IP addresses/hostnames that made requests to your site. 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 site.
Visits occur when some user makes a request for a page on your site for the first time. As long as the same user keeps making requests within a given timeout period, they will all be considered part of the same Visit. If the user makes a request to your site, 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, users who link to graphic and other non- page URLs will not be counted in the visit totals, reducing the number of false visits.
Pages are those URLs that would be considered the actual page being requested, and not all of the individual items that make it up (such as graphics and audio clips).
A Site is a remote user that makes requests to your site, and is based on the remote user's IP Address/Hostname.
URL - Uniform Resource Locator. All requests made to a web server need to request something. A URL is that something, and represents an object somewhere on your site, that is accessable to the remote user, or results in an error (ie: 404 - Not found). URLs can be of any type (HTML, Audio, Graphics, etc...).
Referrers are those URLs that lead a user to your site or caused the browser to request something from your site. The vast majority of requests are made from your own URLs, since most HTML pages contain links to other objects such as graphics files. If one of your HTML pages contains links to 10 graphic images, then each request for the HTML page will produce 10 more hits with the referrer specified as the URL of your own HTML page.
User Agents is a fancy name for browsers. Internet Explorer, Chrome, Safari, Firefox, etc.. are all User Agents, and each reports itself in a unique way to your server. Keep in mind however, that many browsers allow the user to change its reported name, so you might see some obvious fake names in the listing.
Entry/Exit Pages are those pages that were the first requested in a visit (Entry), and the last requested (Exit). These pages are calculated using the Visits logic above. When a visit is first triggered, the requested page is counted as an Entry page, and whatever the last requested URL was is counted as an Exit page.