There are nice pointers here detailing why these companies are succeeding including Dell’s use of Twitter and KLM’s 24-hour customer help.
The one I love though is how when last August when Peter Shankman tweeted at Morton’s Steakhouse: “Hey @Mortons – can you meet me at Newark airport with a porterhouse when I land in two hours? K, thanks”.
Although he was joking Morton’s took note and someone from Morton’s met Shankman at the airport after his flight carrying a Morton’s bag. Obviously it helps if you have more than 100,000 followers, but it is all about listening.