I'm guessing that you are talking about a website.

In theory, you could track unique visits on a per login per computer basis using an ActiveX control. This would have practically nothing to do with Perl though. Said control would have to pass data to the server, and you could use Perl on the server side, but that's about as far as it goes.

It isn't a very good solution though. ActiveX only works in Internet Explorer (and related browsers) on Windows (so say goodbye to anyone using a Mac, Linux, Firefox, a mobile phone, etc, etc). Also, allowing the install of an ActiveX control allows a website to do practically anything to a system - asking for that level of trust just to track unique visitors isn't sensible.

Saner approaches would be based on cookies (with allowances being made for users who don't accept the cookie) or logins (which can tie a session to an email account, or some other piece of evidence of uniqueness (not that an email account is an infallible example of such).

dorward++

In theory, you could track unique visits on a per login per computer basis using an ActiveX control.

Just to make it a bit clearer that this still isn't a reliable method: it confuses visitors (who are supposedly human) with user accounts on specific machines. For one thing, if someone uses two machines (s)he will be counted twice. Also, if more people use the same account on the same machine (quite common, especially on windows or on public terminals) they'll be counted as a single visitor. In short, you won't gain much over a login system or even cookies.

Additionally it should be impossible for any random user of a public machine (or even shared "home" machine, if the administrator has a decent sense of paranoia) to install an active-x control.

"What should it profit a man, if he should win a flame war, yet lose his cool?"

update: the longer I stare at that post, the more I do worry.

i know it only could be done by making active x plug-in and requiring the user to install it

Others have pointed out the error in this process. If you MUST track users -- and I've never really understood that concept, save for ad views -- there are any number of Javascript apps that will do the trick far better than ActiveX. That's with the caveat that Javascript might be turned off, in which case, you're screwed anyway.

I've heard good things about Google Analytics, so that might be a good place to start.