The card is good for a 1 year combined subscription to Wired Magazine's paper and digital editions. Once you activate the card you can choose to get the subscription via the Wired iPad app or the Nook or Kindle Stores. And you do have to have the card activated; it works just like the phone cards and gift cards that you've probably seen everywhere.
As I said, this is new to me. I can't find anything on the Target or Conde Nast websites, and what little info I found on the Wired website at wired.com/target was simply an activation page (with a customer service phone number). I can't even find any sign of this program in Google (now that is weird).
But I did find some technical info. While I'm pretty sure that Conde Nast is handling this in house, the cards are based on a system developed by Incomm called Fastcard. Now that has a website, and apparently there's a parellel program for selling paper subscriptions with similar cards. Also, Incomm has been running a number of gift card type programs for a while now. In fact, I've probably bought one card or another at some point.
Conde Nast is a US publisher with 18 magazine titles and numerous websites. They were one of the first publishers to jump on the iPad app bandwagon, and they were also one of the first to offer the dual subscriptions. With that in mind, today's news is more of a puzzler than a surprise. I'm puzzled by the lack of publicity, not the cards.
Still, I do find it interesting that these cards first appeared in Target. In the past I've said I expected Target to replace the ereader hardware sales (they dropped the Kindle and Kobo Touch) with something that would let them cash in on content sales; clearly they've found it.