In normal operating mode, this setting must be set to 'Visitor Sessions'. Web-Stat will then count one new visitor every time someone starts a new browser session on your site.
If a visitor comes to your site for the very first time a new 'visitor session' is detected. The counter increments by one, and so do the total and first time traffic reports.
If that same visitor reloads your page or leaves your site and comes back within less than 30 minutes, we consider that we are still in the same 'visitor session' and do not increment the counter or the stats again.
If the visitor leaves your site and comes back after more than 30 minutes, we have a new 'visitor session'. We also record the fact that this particular visitor has been to your site before. The counter increments by one, and so do the total and repeat traffic reports.
The monitoring of 'visitor sessions' gives you a very accurate picture of your site's traffic, as opposed to a simple counter which would increment indiscriminately whenever your site is loaded.
Test modeIf you just installed the Web-Stat code on your site, you may want to verify that visitors are being recorded properly (and that the counter increments if you made it visible). The default 'visitors sessions' setting makes this a bit difficult because after detecting your first visit to your site your stats will not update anymore unless you wait 30 minutes or more to load you page again - that's because Web-Stat considers that your multiple visits within a 30-minutes period are all part of the same 'visitor session'.
The solution is simple : set your account type of tracking to 'Test Mode' and every single loading of the page on which you installed the Web-Stat code will be considered a new 'visitor session'. As a result if you load your page and then reload it 4 times you'll see the counter going to 1, 2, 3, 4 and 5. When checking your stats you will see your own visits recorded 5 times.
After testing your account make sure that you set the type of tracking back to 'visitor sessions' otherwise your stats will be inaccurate
Note that the 'type of tracking' setting can be modified at any time in the Control Panel.