Is Delta, or someone else, using Twitter?

Saw Digitas' Greg Verdino today at ClickZ's Advertising in Social Media conference today, where he went on about how someone has created an account on Twitter (think social networking via mobile devices, more or less), purporting to represent Delta Air Lines. Verdino, who notes that Delta is an agency client, isn't exactly sure that this person is acting in any official Delta capacity, but he or she seems to work at the airline and like it, so maybe that's not a big deal. I came home and found a link to it, and found a few interesting microposts, such as: "what do y'all think is the best way for a big company to use twitter?" This story has been circulating on some marketing blogs over the last week or so, but still worth mentioning, if for no other reason than I think those of us who know about it like the idea of someone from a company IMing to individuals about the brand they represent—even if the brand he or she represents doesn't know it's being represented. Wow, this is getting meta.