Do Capitals In Email Addresses Make Any Difference?
May 29, 2019
Mostly you see email addresses that have no capitals, but you
may have seen email addresses that were all caps or mixed caps
and small letters. You may have wondered whether you can do
this yourself when giving out your own email address, perhaps
to emphasize some part of it.
The answer is it shouldn't make any difference, i.e. you can
if you want to ... unless
there is some bad programming
along the way, which there may be given the plague of IT
Email addresses consist of a username, which is that of the
email server computer account, and a domain name, which is the
email server computer's address on the Internet. For example,
in the email address email@example.com,
dr.duane.thresher is the username and alum.mit.edu is the
domain name. Capitals can make a difference in the username
but usually accounts are created with no-caps usernames and
then when an incoming email address is checked, by comparison,
for whether it has an account there, the incoming email
address username is, via programming, automatically made into
no-caps before comparison. Domain names are defined as
no-caps in the standards, so the same no-caps programming is
applied to them.
This is very basic programming, i.e. basic IT competence, but
given the plague of IT incompetence
sometimes caps in email addresses cause problems. I
myself have had this
problem with the U.S. Postal Service (USPS) on their usps.com
website; see The
U.S. Mail SHOULD Be Worried About Email
It's safest to just use no caps in email addresses, but I risk
it in some situations.