This is not a new feature, but one that I recently discovered.
With a single gmail account firstname.lastname@example.org you can instantly set up many many more. How? The Magic lies in how Google handles extra characters in the username.
If your gmail = email@example.com then all of the following variations below will flow into your email account
and so on.
The other side of this is the ability to set up filers in gmail based on this. So you can choose to auto-delete emails or file them away, or apply a label to them. Like I said, not a new tip, but handy all the same