Paperless Post for a while now. From the way my email inbox is looking, it seems to be the new evite, with the added dimension of "not just for invitations" -- they do birth announcements, thank you notes, etc.
The cute designs offer something for everyone, although I have heard some unhappy feedback about there being a cost involved. I love all things paper, so usually default to printed collateral, especially when it comes to invitations, but am always game for exploring something new.
Does anyone have personal feedback on Paperless Post?