Recently, a colleague at work told me a great Gmail trick that I’d like to share here.
You can add a
+ sign at the end of the local part of your email address followed by an arbitrary combination of words and/or numbers.
Emails sent to such variants of your Gmail address will all end up in your Gmail inbox!
This is a really helpful feature when it comes to software testing with multiple accounts. You only need a single Gmail account with a single inbox. Just sign up with different variants of your email address.
Another use case could be to find out who shares your email address with others. To do this, simply sign up with different services using different variants (e.g. sign up at arbitrary-service using firstname.lastname@example.org). You will then see to which variant the unsolicited emails from another provider are sent and know who has shared your information.
Update 2022-08-08: Unfortunately Azure Active Directory (AAD) does not allow
+ signs in email addresses (at least when inviting guest users).