When you create a Gmail account, you actually get two email addresses – one is the regular address while the second email address has in the domain.

That means if your email address in Gmail is something like [email protected], all email messages that are sent to [email protected] will also be delivered to your own Gmail account. That’s two for the price of one.
Like the Gmail plus trick, you can take advantage of these two domains so that less spam reaches your Gmail mailbox. For instance, gGive the address to your close contacts (put that in the visiting card) while keep the address for public (put it on your blog). Then set a Gmail filter such that all email messages with in the header go a special folder so you will never miss important email from close friends.

And if you multiple Twitter accounts, associate one with your main address and the other with your new address.