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Plus Addressing email addresses in Microsoft 365
Plus Addressing email addresses in Microsoft 365

This week I received a new subscription to my newsletter and I noticed the email address looked a tad strange. The email address contained +powerassist which I instantly knew would not be part of someone's official email address.

After a bit of research I found out that Microsoft had introduced support for custom email addressing with Microsoft 365 email services. This is commonly known as Plus Addressing and is a standard that allows users to extend their email address using "tags" or the plus (+) character.

A user with the email address of username@domain.com.au can use the plus addressing feature to extend their email address to username+tag@domain.com.au and all emails sent to the username+tag@domain.com.au email will land in the user's username@domain.com.au inbox.


The "tag" can be unique, allowing users to generate an infinite amount of custom email addresses, which they can give out to companies in newsletter sign-up forms, contact forms, and other online forms. Once emails arrive in the user's inbox, the owner can see where the email came from by the email address the sender used.


Now the user that subscribed to my newsletter can now easily distinguish my newsletter emails and there are many advantages for doing this.

  • The user does not have to contact the IT department to create an alias mailbox.
  • The user can create an infinite amount of email addresses and easily do it themselves.
  • Custom message rules can easily identify incoming emails.
  • For example if a company refuses to remove you from there mailing list you can create a message rule to automatically delete the tagged email address.
  • Identify companies that are sharing your email address with other companies.
  • For example if you start receiving emails from a company that is using an email address tagged to another company, you know the company you gave the email address to has shared your details.


This feature is also available with Microsoft's outlook.com and hotmail.com email services


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