1. Suppose I have an email account "email@example.com" on Gmail And I have already registered member on forum with username as "abc".
2. Now if I try to get account using same email address "firstname.lastname@example.org" then forum system will give me an error as "An account with this Email is already registered !".
3. So to bypass this restriction, just put "+1" after id of email address. Now my modified email address will become "email@example.com".
4. Use this modified email address while registration of account on same website with different IDs.
6. All the emails including confirmation emails, subscription emails will receive on your default email address. In my case all emails will receive on "firstname.lastname@example.org".
7. To create more accounts on same website, just increment the number after "+" sign. That is "email@example.com", "firstname.lastname@example.org" and so on.