Here's the secret.
Hey, what did you expect?
Having just attended the Direct To Consumer Symposium (DTCS) on Tuesday, I can say that everyone wants to know how to forecast the ROI for social media. It seems pretty clear that it's hard to measure (although there are definitely things you can measure, it's not easy to equate them with hard dollars in your bank account).
The big issue for wineries, large and small, is that Twitter (and other social media venues) takes time, which means a person. And that person costs money. And that has to get paid for, somehow. Which brings us back to ROI.
Fundamentally, you either have to believe in social media, or you have to be big enough to afford the experiment.
I tend towards the view that social media has value, but it's primarily the sort of value associated with having a pleasant, competent person answering your phones.
On the other hand, Rick Bakas of St. Supery gave a case study of using Twitter (plus a landing page) to sell 250+ cases of their 2003 Merlot (at $150 a case, including shipping, it was a terrific deal). Of course, he also pointed out that two subsequent offers didn't garner as strong a result. It appears that offers need to be spaced out to avoid "offer fatigue."
(Disclaimer: I bought one of those cases.)
So, how are you trying to make $$$$ with Twitter?