Chessmaster1000: Aye, the IP address can be used to help in these matters. At one forum site that I enjoyed for a while there was a self-appointed "IP Police" who took it upon herself to detect multiple nicks by collecting posters' IP addresses. It's fine when the user has a static IP address but there are many ISPs which assign a new IP address at the start of each session. (Very common with dialup and is still pretty common with broadband.) Even so, there will be a commonality. For instance my IP address is never the same but does always start with the same two numbers.