I was wondering why using foo.bar@gmail.com works but not foo.bar@outlook.com.In Gmail, foo.bar@gmail.com and foobar@gmail.com (and any combination of periods in the username) is equivalent.Is this a hidden feature in Gmail?
Same e-mail user, different address?
gmail;email;outlook;windows live mail
We could say this is kind of a hidden trick of Gmail. Here is what Google says about it:Gmail doesnt recognize dots as characters within usernames, you can  add or remove the dots from a Gmail address without changing the  actual destination address; theyll all go to your inbox, and only  yoursAnd the makeuseof article about it.Microsoft didn't choose to provide this for outlook, probably because they migrated the hotmail accounts where the . (dot) could be used a character in the username.Note that you also have two similar tricks:the mymail+anything@gmail.comthe mymail@googlemail.com is equal to mymail@gmail.com