LOL, AFAIKBZITE, I personally have been served both a summons and a subpoena by e-mail. Of course, that's because my privacy protection paid off and they had no idea how to serve me, and the judge authorized e-mail since I had e-mailed them in the past. It was pretty awesome to face off three $500/hour lawyers who admitted they had no idea who I was or how to identify me, and would I please give them more info? Nope. Judge sided with me. But I digress...
It feels a little awkward to add AFAIKBZITE when he's already given an incorrect answer, but rules are rules.
If you're the subject of a suit, you'd get a summons, not a subpoena. The standard subpoena is an order to appear on someone's behalf, typically to be a witness, but not as a party to the proceeding. A subpoena duces tecum is an order to appear and produce relevant documents. In some places I've been told that the latter can be satisfied by providing the documents without appearing in person.
Anyway, of course we all know this is spam.