GMail Plus Addressing is not new but still very relevant and useful trick to help save your GMail mailbox from spam. And if you get spammed, you know exactly which website / online service leaked your email address to spammers.
[Was reminded of the GMail plus trick after an email subscriber actually used it today while subscribing to the DI newsletter - see screenshot above]
What is GMail Plus addressing? Say you have an email address like billgates@gmail.com. If you append a "plus" sign to your email username, gmail will ignore anything written between the + and @ sign.
So any email address sent to billgates+microsoft@gmail.com or billgates+blog@gmail.com or billgates+website@gmail.com will still reach your billgates@gmail.com inbox though technically, they are three different email aliases.
When you share your email with some non familiar service, like a newsletter, you can supply your existing email with a plus sign. If you ever receive spam addressed to that email alias, you know the exact source that's sending the spam and can easily block all emails using a GMail filter.
[type the alias in the To: fiedd and redirect all incoming message to Trash or apply a new label]
More GMail Easter Eggs [including the dot trick].