Okay so I've set up my wedding website, complete with electronic RSVP page. Most of my friends are young and would rather have the convenience of RSVP'ing electronically rather than by snail mail. Some other of my friends, I don't know how they'd rather RSVP. So do I include stamped envelopes for the friends I don't know about or not? I don't want to be rude, but I don't want to waste precious budget money either.