Social media expert James Andrews could have given himself some better advice about using Twitter, the mobile micro-blogging service. Andrews is a vice president and director for Ketchum Interactive, the digital division of the mega public relations agency.

Dispatched from his home base in Atlanta to Memphis to meet with FedEx, one of Ketchum's top clients, Andrews casually tweeted, "True confession but I'm in one of those towns where I scratch my head and say, 'I would die if I had to live here.'"

Ironically, his Twitter handle is "keyinfluencer." Andrews evidently didn't take his self-anointed status very seriously.

Some eager social media beaver in the FedEx corporate communications department was following Andrews, read the tweet, and took immediate umbrage. After his talk at FedEx, an employee lambasted him in an email that questioned his judgment, defended the city's revitalization efforts, pointed out that the employees he'd just addressed had taken a 5 percent pay cut to support the company, and questioned the expense of paying Ketchum for the presentation.

This disgruntler also copied top communications executives at FedEx and Andrews' bosses at Ketchum, as well as PR guru Peter Shankman, who made the email public without revealing the employee's identity.

Andrews was trashed on Twitter and blogs for dissing the hometown of an important client, while FedEx took heat for the take-no-prisoners missive of its rogue employee. Certainly, both could have behaved better, and this is a terrific reminder of the difficulty of private discourse using social media.