Lots of people still ask, "Does your e-mail ID use capitals or lower case?" But that question is a technical no-brainer, because it simply doesn't matter whether you use capitals or lower case -- meaning small letters -- in an email address. The email will be delivered anyway: you may type the address with all capitals, all lower case, or randomly combine both.

Yet there's one place where capitals can secure your emails: in your password. Having a password like "ScoRPioN" or "sCorpiON" instead of a plain "scorpion" makes it tougher to hack.

You might also be surprised to note that having an email address like "John.Smith@gmail.com" on Gmail is equivalent to "JohnSmith@gmail.com" or for that matter even any other combination like "J.ohnSmith@gmail.com" or "J.o.hnSmith@gmail.com" or "Jo.hnSmith@gmail.com".

That is, Gmail does not consider "." as part of the email address and removes all "." from the email address before delivering messages to the particular inbox. If you have dots in your gmail address or even if you don't have a dot, just try sending yourself and email by placing a dot somewhere or switching the position of the dot in your email address, before the @ symbol but ofcourse and look you've got a mail!.

It also means that if someone already has an email address say "a.bc@gmail.com" then all other combinations of the same letters in the same order with different numbers and positions of dots will be unavailable for signup. For example "abc@gmail.com" or "a.b.c@gmail.com" or "ab.c@gmail.com" will be unavailable for signup in the case of the above email address.