Starbucks is looking to Twitter to combat falling sales in its massive network of stores. The coffee giant is launching a new ad campaign that hopes to leverage its massive numbers of followers and fans online to get to their friends and acquaintances.

According to The New York Times:

“The coffeehouse chain is putting up new advertising posters in six major cities. To further spread its message, it is trying to harness the power of online social networking sites by challenging people to hunt for the posters on Tuesday and be the first to post a photo of one using Twitter.”

The ads are meant to emphasize the quality of Starbucks coffee and the company’s overall attention to detail. One tagline will read: “If your coffee isn’t perfect, we’ll make it over. If it’s still not perfect, you must not be in a Starbucks.”

This will be the biggest marketing campaign that Starbucks has undertaken, and comes just as McDonald’s has joined the market with McCafé, it’s own line of higher end coffee products. McDonald’s has reportedly spent $100 million on television, print, radio, billboard ads to promote these new products.

But Starbucks’ campaign generally plans to avoid traditional advertising, hoping to make use of the company’s ardent base of followers online. From to The Times:

“Starbucks says it thinks its campaign will be helped by its 1.5 million fans on Facebook and 183,000 followers on Twitter. On the Saturday before the presidential election, Starbucks sponsored a single 60-second television commercial on “Saturday Night Live” advertising a coffee giveaway on Election Day. Starbucks then posted the video online. By Tuesday, it was the fourth-most-viewed video on YouTube, and people were mentioning Starbucks on Twitter every eight seconds.”

Starbucks certainly has a large base to exploit for online marketing, but aggressively marketing through them may not be such a good idea. While many Twitterers will be more than happy to send a tweet or two in exchange for a free coffee, the friends receiving those messages might not be so amused.

And if Starbucks alienates potential new customers and others that they are hoping to bring back into the fold, the whole thing will be for naught, no matter how much money they saved by avoiding traditional ad venues.