That's important to note, I know specifically that some non-major service providers (meaning: not Verizon, Comcast, etc.), sometimes don't even show you what spam you get. So, if your using a smaller service provider and you still haven't got it and its also not in your "spam box" there's likely two things that happened.
A) You didn't put your email in your profile "email" box. I would direct you to pg's post last night but its gone now.
B) Your service provider may use a special filter in front of your mailbox which means not only was it marked as spam but it was marked before it actually reached your email and just got tossed overboard in cyberspace. Though, one would expect the number of people to suffer from this problem to be small but it does happen.
What's unfortunate is if that e-mail that got lost was an invite. =C