Some websites like LinkedIn, Quora, Facebook etc. let the user enter one or more email addresses. The user can make one of them as primary account and they show him all the emails he entered so he can make any one as primary any time.

why they need that? and why the users need that?

4 Answers 4


Another answer is that you cannot know how your addresses will develop in the future. If you want to regain access to an account you have not used for a long time anymore, you might have lost one or more of your email accounts in the meantime. People change provider, change jobs and/or change services. If you allow associating an account with multiple email accounts, you limit the risk of loosing access.

  • That is mainly relevant if your email address is also your username. Commented Jun 28, 2012 at 19:59
  • 2
    @Danny Varod: no, because the email address is often needed for password recovery too. And do you remember a password you have not used in years?
    – André
    Commented Jun 29, 2012 at 5:17
  • Personally I do remember usernames and passwords I haven't used in year, it's the ones I have to change every 2-3 months (for no good reason) that are annoying. Commented Jun 29, 2012 at 10:11
  • Ok, I should have said: I don't remember a password that I have not used in years. Perhaps the majority of internet users have far better memory for that than I do. Or perhaps not.
    – André
    Commented Jun 29, 2012 at 12:20
  • I think I'm the one with the non-standard memory, not you :-) Commented Jun 29, 2012 at 12:27

For the search functionality.

You can search for users you know by their email address.

Also, that way you can send different messages with different reply to email addresses.

  • Hadn't thought of that; that would be useful for Facebook and LinkedIn
    – Zelda
    Commented Jun 28, 2012 at 14:33
  • +1 I didn't think of that either. I would say that this probably is among the main reasons! Commented Jun 28, 2012 at 18:07

It's basically to have a range of emails that serve different purposes and are displayed to different people.

With Facebook for example, you may sign up with an email that you only use for signing up for services and don't use for other communication. In that case you don't want that email to be the one displayed for other people to contact you through. Therefore Facebook allows you to add an additional email that can be displayed publicly or to specific groups in your social network.


For one thing it allows one to log in under any email you own; for example on Gravatar I can log in on both my primary [email protected] and secondary [email protected] addresses, and both log "me" in because both are claimed by me and associated.

This makes particular sense with email related clients; Gravatar's settings are dependent on your email, so it makes perfect sense to add multiple emails. For other clients, even if you can't use more than one email within the app, they serve as extra logins so you don't forget "Oh, which email did I sign up for Facebook with?"

When an app lets you set a "primary" email, generally that means that's the email which will get all notifications/newsletters/ect from the service. Setting up multiple emails can be used to easily change this in case you deactivate or rarely use an email.

  • This is the answer I'd have given. One other example I mentioned in this answer on a similar topic was TripIt, which accepts emails forwarded from any of your specified email addresses as travel itineraries. Since you might use the service with business and home email addresses it makes sense that you can combine them both into one account.
    – Kit Grose
    Commented Jun 28, 2012 at 14:36

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