Referring to AllPosters.com? I mentioned that technique during the beta, but nothing came of it, and I've yet to have the opportunity to experiment with it specifically within BVC5. I don't think it would be too difficult, but would take a developer for sure, to have one generated. It's a great idea.

Now, you could create a coupon that is allowed one use per customer, and put that in your packing slip template's HTML. Maybe switch it up every once in awhile. If people pass it around, it doesn't matter; it's doing it's job of attracting new customers. Without an expiration, of course, but that doesn't mean you can't say 'use within 30 days'.

Well, that's what I'm saying. You encourage striking while the iron is hot in your wording, without an actual expiration existing, if you don't go the development route. Just build a template and switch out the number, like you said, two or three in rotation.

Doesn't have to be all that frequent, but you do end up in a quandary when the same frequent-shopper gets the same coupon more than once, but can only use it once. So the plugin route would definitely be more efficient.

Yeah, I meant to mention inserts. Getting creative with pre-printed inserts goes a long way in keeping them coming back. I mean really creative, especially if you're running something boutique-style; making them piece together insert cards from different orders like a puzzle to get the full discount code, for example.

There are so many ways to make it fun, depending on your store, of course, and as long as you realize that great design is going to be 90% of it's success. Place an order at Threadless for some good examples of creative inserts.