A: No! This is a very recent trend, and one I hope doesn't last. When done, guests are asked to fill out an envelope with their name and address when they arrive. Sometimes these are used to draw door prizes, but either way the bride then jots off the thank-you notes for her gifts after the party and puts each in their pre-addressed envelope to mail. This trend makes light of the act of writing a thank-you note; though it takes time to handwrite out addresses, the effort should be made by the bride, not her guests. If you aren't sure of your guests' addresses in this electronic age, provide an address or guest book and ask each guest to fill theirs in when they arrive, or ask the hostess for the addresses from her invitation list.
It's also worth noting that even though the bride thanks her guests in person for her presents when she opens them at the shower, a handwritten note is still required. —Anna Post, The Emily Post Institute