Even for a winery, which can't create products on the fly, it does point to the value of having devoted followers (not just quantity, but quality) and making special offers to them.
Do you have your Facebook and Twitter information on a nice little sign next to the cash register in the tasting room? If not, you're missing an opportunity to gain followers. Of course, that little sign should also point out the benefits of being a Fan or a Follower of your winery (cool offers not available to anyone else, of course!).