Similar to the Gmail Dot feature and the Googlemail there is one more feature in gmail
By adding + sign followed by some text at the end of the username will also lead the email to the same mail box.
Emails send to [email protected] = [email protected]
Though there is no official word from google about this feature it working and well know.
These features can be utilized in multiple ways. There are rumors that this is a bug and can be discontinued by google anytime.
There are multiple uses of this feature some of which I have listed here.