You know when you register with forums such as this one, they send you an e-mail address and ask you to click on a link to complete the registration. This is to filter out bogus registrations I imagine. I was just wondering how is this achieved in practice? What do you put into the link that you send the user so that you can know when they navigate back via the link that they are a valid user? I would like to add the same technique to my own web site.
Any ideas greatly appreciated.