im curious as to what sortve individual identifiers sites employ to tag visitors. is the identity predicated solely on the ip address, or does each computer have a unique, unchanging token associated with it (speaking outside of cookies).
IP address isn't a reliable identifier. It's OK for blacklisting trouble-makers. Bad for identifying users or machines.
Tag anonymous visitors' machines with a long-lived cookie. Tag the visitors themselves with a username and password, if you can!