Just in case anyone is traveling down that way and enjoys wine tastings! Read on ...
Most (but not all) Visa cards these days are "Visa Signature" cards. The way you can tell if you have one is to look at the Visa logo on your credit card(s), on either the front and/or the back of your card. If it is a Visa Signature card, it will say so. This is important for this deal (as you will see below). If you do not have a Visa Signature card, feel free to ask me which card(s) I would recommend. There are some (like the Chase Freedom Visa) that don't even have an annual fee.
So here's the "deal" ... for all of 2015, Visa Signature cardholders can get free wine tastings at a LOT of different wineries in Sonoma.
The Visa Signature website won't allow a direct link to this deal (you have to look down a ways on THIS page), so I'll post a photo/image of the deal:
HERE is a map of the participating winery locations.
And HERE is a blog post from a "deals" blogger where I found this information - including their personal experience with the deal.