33

E.g.: If your Gmail ID is abc.xyz@gmail.com, it considers this the same as abcxyz@gmail.com.

Why is this so?

migrated from superuser.com Apr 20 '11 at 10:13

This question came from our site for computer enthusiasts and power users.

  • What can we do if they want that? Do you know that some providers does not allow different characters than alphanumeric? Gmail accepts "." and "+". "+" is for address aliases (e.g. your.addr+alias@gmail.com , where "alias" can be any alphanumeric string (with some limitations I don't know). – kokbira Apr 20 '11 at 12:15
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    Very early accounts are affected by dots in the names though – Eight Days of Malaise Apr 20 '11 at 16:54
  • I was not aware of that fact, sure saved me the time of registering both accounts in case someone steals my name (which pretty much answers your question too) – Asaf Apr 20 '11 at 20:02
  • Humorously, it doesn't matter how many periods you use. ie, abc.............xyz@gmail.com is also identical. – Yahel Apr 21 '11 at 3:15
  • Because it's cool to have! – Lipis May 5 '11 at 12:42
31

It's done that way to prevent confusion (and possibly impersonation). I'd rather not have brianwhite@gmail.com get my mail simply because somebody left a dot out when typing my address of brian.white@gmail.com. (Note: Neither of those is actually me; I was too late registering to get anything even remotely close to my real name. :-)

Also, you can append anything to your username with "+something" and it'll still come to you. With this, you can create unique email addresses for certain things and then filter on it or just be able to tell which sites are selling your email address to spammers. (Note: some broken sites don't allow "+" in an email address even though it's supposed to be allowed.)

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    He beat you to the Gmail username and now you punish him with spam, fair enough I guess. :) – Trufa Apr 20 '11 at 14:39
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    @Trufa Not a big deal, since he has the Gmail spam filter protecting him. – Yahel Apr 21 '11 at 3:16
  • The +ext is very common among MDAs and was around long before gmail. The ignoring of certain characters to create a "canonical" name is also reasonable when considered in the light of avoiding mis-routed messages and impersonation. As for as I know, there is nothing in the RFCs that disallow this; MDAs are largely allowed to route mail as they see fit, hence the support for aliases, filtering, and forwarding. In that light, ignoring dots is no different that creating aliases. – Brian White Sep 2 '17 at 19:00
  • @Physics-Compute What "both issues" are you referring to, and what standard do you think they violate? As far as I understand, everything to the left of the @ is considered by SMTP to mean whatever the receiving server wants it to mean; there's no expectation that each possible string represents a different inbox, or even that there is such a thing as an inbox at all. – IMSoP Jan 10 at 14:42
  • @IMSoP I believe it does state that each combination of acceptable characters must represent a discreet different address (including different address for capital/non-capital letters), but does not dictate that they need to represent a different inbox. Yes, aliases are allowed, so I've deleted my previous comment. If they did not allow an address based on presence or nonpresence of a dot, then that would be against the standard, which is how I originally misinterpreted the question. – user165026 Jan 10 at 19:08
11

From Gmail Help:

Gmail doesn't recognize dots as characters within usernames, you can add or remove the dots from a Gmail address without changing the actual destination address; they'll all go to your inbox, and only yours. In short:

homerjsimpson@gmail.com = hom.er.j.sim.ps.on@gmail.com
homerjsimpson@gmail.com = HOMERJSIMPSON@gmail.com
homerjsimpson@gmail.com = Homer.J.Simpson@gmail.com

All these addresses belong to the same person. You can see this if you try to sign in with your username, but adding or removing a dot from it. You'll still go to your account.

...

One last thing: Google Apps does recognize dots. If you'd like to have a dot in your username, please ask your domain administrator to add your preferred username as a nickname.

  • 1
    What is the use accepting dot while creating new registration. – Srinivas Tamada Apr 20 '11 at 9:46
  • e.g., when adding someone as an user of a shared document using Google Docs. – kokbira Apr 20 '11 at 12:14
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    The question is: Why? – user8720 Apr 20 '11 at 13:11
  • I'm guessing for some reason they took a design decision not to treat dotted addresses differently to avoid emails being routed to the wrong person. E.g. if barack.obama@gmail.com was getting barackobama@gmail.com's emails. – Gaff Apr 20 '11 at 13:16
4

It is a lesson in human nature that so many experts simply recite Google's pat answer on this as if an assertion were identical to empirical reality. I am one of the early account holders with the firstname.lastname@gmail.com accounts. About three years ago, I began receiving email directed to firstnamelastname@gmail.com. By triangulating the information I was able to glean from their dry cleaners, car dealer, etc. I was finally able to contact these people (about 3,000 miles from me, BTW). The DO have the same account as me, minus the period. We were able to determine that only a portion of email "leaks" across accounts. Unfortunately, the fact that I had my account 10 years before they had theirs did not convince them to leave the account to me. Thus, I live with the occasional notice from the bank, school, etc. Because of this, I no longer use Gmail for anything important or confidential.

The most disturbing thing to me is Google's insistence that they could not have made a programming mistake when they clearly did. These folks are arrogant in their faux humility.

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    Except for the ranting, this might be a useful answer. – ale Mar 1 '16 at 16:33
  • This was already acknowledged in a comment: "Very early accounts are affected by dots in the names though" – user79865 Mar 2 '16 at 1:18
  • +1: I have the same issue myself (mutatis mutandis), at least in the sense that I receive email (such as Amazon purchases, some adult dating 'connections', etc.) which are intended for a different user. My name is a common one, apparently. In most cases, I have no way of contacting these folks. I hope they do not receive my email, your answer seems to dash that hope. I have received all manner of email such as secure military documents (US, UK), political documents (EU, IRL), etc. – copper.hat Apr 9 '16 at 20:44
  • I started facing the same problem - yes I am receiving someone else's emails - since 2011. But a lot of my social networking profiles (including stackoverflow profile) are built using this email address, so I am finding it difficult to move to a newer email address. And I also doubt I've missed some important emails that were meant for me but reached the other recipient. It sucks! – whereDragonsDwell Apr 22 '16 at 11:14
  • Early on, it's possible that there was no "canonicalization" of email addresses (i.e. removing the dots) to create the base, hidden userid. Thus, creating the new one didn't detect a duplicate. I'm really surprised that you don't have more problems than a couple mis-delivered emails. – Brian White Apr 20 '17 at 0:16
2

Gmail likely supports this use of periods in the email address in order to comply with the IETF's email address formatting standards. If you'd like something less verbose, Wikipedia's page on email addresses simplifies understanding their use (and probably reasoning) well.

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    The standard says that a.b@foo.com must be accepted by intermediate systems, but not that foo.com must assign that name to anyone, or to the same person who owns ab@foo.com. – Random832 Apr 21 '11 at 15:32

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