Today I received an email from a hotel, confirming a reservation for a
room.  But it wasn't meant for me; it was meant for "Kathy Fogel"
(whom I've never met), and was sent to "k.fogel@gmail.com".

Now, I do have the account "kfogel@gmail.com", but I'd never received
email for "k.fogel" before.  As I'd always thought "." was a
significant character in email addresses, I didn't see how I could
have gotten this mail.  It turns out, though, that Google ignores "."
when it's in the username portion of a gmail address.  My friend Brian
Fitzpatrick knew this already, and pointed me to Google's explanation:

   http://mail.google.com/support/bin/answer.py?ctx=%67mail&hl=en&answer=10313

The above page doesn't say why, but we know why the '.' has been given a
similar role in other large email systems. Optional and automatically
ignore delimiters, like '.' in the Google case, can play an important
role in handling merged databases of email accounts -- something that
seems possible in the GMail case.

It's possible that, like others faced with the prospect of merging email
systems, Google had several different sources of user accounts and that
each database had different rules about which characters were allowed
and which weren't; some of these systems may also have been ignoring
invalid characters under certain circumstances, just as gmail does
today.  But this new Grand Unified Database would have to be restricted
to the intersection of all the character sets of the source databases,
even if that means (in some cases) not directly supporting common
characters (such as ".") that are allowed by the Internet-wide email
standard.  Furthermore, they can't just reject those characters; if any
of the old systems treated them as though they weren't there, then gmail
would have to do the same.  Thus, "k.fogel@gmail.com",
"k.fo.....g.......l@gmail.com", and infinitely many other gmail
addresses will all reach me.

Anyway, I called the hotel, and eventually managed to make them
understand that I had no idea who Kathy Fogel was, and that I'd
accidentally gotten an email intended for her.  They said they'd
resend, and of course I said "Wait, no, it'll just come to me again!"
But they swore they had a different email address on file for her, and
indeed, I haven't gotten a second email.

Which raises another question: how did they send the mail to
"k.fogel@gmail.com" in the first place?  Clearly, Kathy Fogel cannot
have that address, because Google will not allow any other "dot
variants" of an address to be registered after the first.  (Besides,
if she did have that address, we'd be getting each other's mail all
the time, and we're not.)  It's also unlikely that she mistakenly
given them that address herself, since they already had another
address in place by the time I called.

A computer wouldn't substitute domain names in an email address like
that.  The only thing I can think of is that somehow, humans are, at
least in some cases, intimately involved in sending out confirmation
emails from DoubleTree hotels.  I say "intimately" because this was no
mere cut-and-paste mistake.  Someone had to transcribe an email
address by hand, and accidentally put "gmail.com" where the original
said "yahoo.com" or "aol.com" or whatever.

I hope Kathy has a nice trip.