For a moment then I thought you'd hacked into my messages, then I realised it was my visitors board! Haha!
Erm, you do know that IP addresses change regularly due to them being dynamic, just because someone has the same IP address doesn't necessarily mean it's the same person if the posts are days apart. Only big companies use static adresses.
vBulletin records all your IP addresses and the mods can cross reference an IP address against anyone who's used it. It's not impossible that two accounts might use the same address in a longish period of time, but three or four on the same forum starts to look suspicious.
I think, and I'm no computer person, that it's a unique identifying number. The IP bit just indicates to the computer/server receiving the information that the following string of numbers is an IP address, meaning it identifies an internet user. If that helps? Internet Protocol is just a way of using the numbers to means something.
Sorry to pester, but could everyone aware of LewisWDC's decent posting alter-ego take the first 2 initials of his name, and check them? Everyone loves cryptic messages right?
An IP is not specific to your computer (Thats a MAC address) The IP address that would be picked up here is the gateway out/in from your router into the cloud. Not the Ip address that is assigned to your machine in your network. Some routers ask for new IP addresses when connected. And some people (possibly office based) use a proxy to access a website via. I could go into more detail if you want (by the way I work in IT) Thats an ISP (s = service)
I that was posted elsewhere before, but it is quite a good one. Some of them can be really rubbish, but thats not bad.