HTMLfixIT statistical hit counter.
The Stats counter is a page counter that doesn't require SSI. It is invisible and collects data from your visitors like Screen resolution, Browser version/type, operating system and refering pages (and unique/non unique page counts). All of which is displayed in a password protected admin page. It can also capture data often blocked by software firewalls.
See: <a href="http://htmlfixit.com/free.php#stats_counter">statistic al counter</a> for details, instructions etc.