Got an e-mail from Webshots:

We're just dropping by to make an offer you can't refuse: Send some postcardsâ??and the first one's on us! Once you see how easy it is to create and mail postcards through the Webshots store, you'll want to send one to everybody. Hurry, this deal is good for the first 5,000 customers (limit one free 4.25"x6" postcard per customer), so send yours today! (The discount will be applied at checkout).