Yesterday the Boston Globe published a good article about companies that respond to complaints voiced on blogs and social media. Two anecdotes:

C.C. Chapman ... blasted a quick gripe about Comcast into the online ether, using the social network Twitter. Minutes later, a Twitter user named ComcastCares responded, and within 24 hours, a technician was at Chapman's house in Milford to fix the problem.

when Travis Johnson, known by the Twitter handle, "pastortrav," complained recently about Southwest's check-in process, he received a quick, public response from an airline employee

We covered Dell in the past; the article has some followup data:

At DellIdeaStorm.com, a social website that the company launched in 2007, people are invited to make suggestions for products and services. Of more than 9,000 suggestions, 50 have been implemented, the company said.

Also mentioned (though without a link): brand monitoring service TNS Media Intelligence/Cymfony.

An aside: it's interesting that the picture and caption changed during the day. I included both above.