Interested in checking out a big brand that’s doing really awesome things with social media? Check out Whole Foods. Whole Foods is the world’s leader in natural and organic foods, with more than 300 stores in North America and the UK.

This week, they’re hosting their second “Twitter Tasting” where they will lead a virtual tasting tour of featured Bordeaux wines. The first Twitter Tasting they did was around the holidays when they encouraged participants to sip, swirl and talk about six of their “Top 10 Holiday Wines.”

So how does a Twitter Tasting work? You print out your tasting sheet ahead of time, then at the appropriate time, you can either join the chatroom or simply follow @WFMWineGuys and #WFMWine to partake in an open discussion with people all over the country who are sampling the same wines you are.

All the wines featured in the upcoming Twitter Tasting can be purchased at Whole Foods stores for under $20. This a great excuse to invite some friends over for a wine tasting party!

This is a great promotion in that it’s totally unique, it encourages interaction, it stimulates buzz and gets customers into Whole Food stores. Because it’s exclusive to Twitter, it’s virtually no cost to Whole Foods (aside from the time invested) and it serves both marketing and pro-active customer-service functions.

Another way Whole Foods is really making their Twitter presence stand out is that they have a page on their website designated specifically to Twitter. Not only do they introduce their main Twitter account, but they also have accounts for specific topics (ie. @WFMCheese, @WFMWineguys and @WholeRecipes) as well as accounts for specific regions and, finally, individual stores. The page is organized and straightforward, simple for even the newest tweeter to explore.

Aside from that, they’re updating regularly, interacting frequently, posting unique content and have a higher Klout score than the majority of people.

Whole Foods has nearly two million followers. Meaning, even if just 1% of them ever set foot in a store from a promotion like a “Twitter Tasting”, that’s 20,000 people. If even just 1% visit the website, that’s 20,000 unique visitors. The ability to reach this large an audience via one portal is unprecedented and this a great case study to illustrate that.