Give 'em an inch and they'll take a mile. Consumers on Facebook Inc (NASDAQ:FB) are excoriating fast-food sandwich shop Subway for selling "footlong" subs that come up short. About an inch short.

When a picture appeared on Subway's fan page showing one of its sandwiches alongside a ruler indicating it was just 11 inches long, not 12, it quickly went viral and soon others were posting their own pictures of their hoagies not measuring up. Now two aggrieved New Jersey men are suing the chain in what they hope will become a class action suit because they say over a six-year period, consumers are losing $0.45 to $0.60 due to the size difference.

It used to be said the shortest amount of time measured was between when a New York City traffic light turned green and the car behind you blew its horn. Nowadays it might be when a company experiences a social media faux pas and a lawyer is in court trying to wrangle a hefty settlement out of them.

I've got my eye on you Once again companies are confronted by the risks associated with having a social media presence. Whether it's on Facebook Inc (NASDAQ:FB), YouTube, or Twitter, engaging consumers on social media platforms hazards the chance the effort backfires. But because Facebook Inc (NASDAQ:FB) has more than 1 billion active monthly users, Twitter features 500 million registered Twitterers who send over 175 million tweets every day, and over 800 million unique users watch more than 4 billion hours of video on YouTube each month, they're just too compelling to ignore.

Yet it also means that somehow, somewhere, something unflattering is bound to show up.

Last year McDonald's Corporation (NYSE:MCD) thought it would be hip to have customers share their favorite feel-good stories about the hamburger chain at the Twitter hashtag #McDstories. Unfortunately for the burger joint, the tales they wanted to tell were horror stories that generated tons of bad publicity.

Yum! Brands, Inc. (NYSE:YUM) thought it would re-create the buzz of "boxers or briefs" by having its Pizza Hut chain offer free pizza for 30 years to a knucklehead willing to ask during the presidential debates "Sausage or pepperoni?" Purposely demeaning the electoral process for corporate publicity didn't sit well with the social media crowd.

The Gap Inc. (NYSE:GPS), American Apparel Inc. (NYSEAMEX:APP), and Urban Outfitters, Inc. (NASDAQ:URBN) all thought it was a good marketing tactic to encourage people via tweets to do some shopping during Hurricane Sandy. Again, cheap promotional ploys driven by calamity didn't really resonate with Twitterers, who lambasted the retailers.

That's my job! Unfortunately, it doesn't even have to be boneheaded corporate pushes that generate negative social media buzz. Employees can do the dirty work for you, crushing in a moment of stupidity years of hard work and millions spent building goodwill. You were probably one of the 8.9 million people who watched the YouTube video of the FedEx Corporation (NYSE:FDX) driver tossing a computer monitor over the fence, a costly error that easily countered years of brand-building through its slogan "When it absolutely, positively has to be there overnight."