> How does one make a proper _poll_ on the Internet?

A first way is to removed duplicate client's IP. That's not
enough but it is better than to accept every single request :)

You can play with cookies, but this can be by-passed.

You can request to download an ActiveX which will read the uniq
processor ID, but this is only for Windows platforms.

Anyway these are some ideas, I do not know a way to do real/unbiased poll
on the Internet.