I notice a lot of users have many alts to abuse various signature campaigns, airdrops and other things. This makes me wonder how many users here are unique, and how many may be from alts etc?
There's no way to tell really..
An administrator could be looking at all the IP's, and see how many uniques there are, but that's far from being waterproof aswell, ( since the forum allows TOR, VPN, etc, you could be sharing an IP with somebody else..).
Other then that, i don't think the forum implements any sort of (flash) cookies, so even they won't have statistics on this.