Introduction
My advertising system sells advertising on a CPC (cost per click) basis, not
CPM (cost per thousand impressions).
It is therefore very important that my clients' clicks aren't being "used
up" by malicious users clicking ads over and over, or by programs like
spiders, crawlers and robots who visit the site and click on every link in
sight!
The first idea I implemented was to only count one clickthough per IP address
per day. I didn't want to use a database or file to store the IP addresses,
and then search for them - that's a little over the top. So I had the idea
that I'd use an Application variable - which would get emptied each day.