We are a very technology based society to the point that we often cast off age old customs in favor of ease.
When it came time to print my wedding invitations my husband and I picked very different invitations but they fit us to a tee. But for RSVP instead of a traditional response card I chose to have people call me or email me to RSVP for a few reasons...a) it is more environmental, b) I am not a fan response cards because I'm horrible about returning them. I will tell you that I did receive some grief from older family members but everyone else loved it. Would I do it that way again...yes for a second wedding like ours probably not for a first wedding. We also had a wedding website to give everyone information about the wedding, about us, about VA, etc. People liked that too. Some people suggested I send an email invite. I couldn't do that...I didn't need formal but I couldn't go that relaxed.
My sister-in-law is getting married and the woman in charge of her shower asked about sending evites instead of mailing. I've been to many showers that used evites and I think it is fine. Although she made a good point...it is nice to get a note, a card, or an invite in the mail. But in my house it is also possible for it to get eaten by a dog or lost on my kitchen counter for a day or two.
My Granny sent us a card for every holiday from St. Patrick's Day to Christmas and I admit I still think of her when I'm in Hallmark looking at cards. And I loved getting the paper card in the mail...it wouldn't have been the same to get an email.
So how about you...you ok with an email or do you want a written invite?