While it is important for journalists to have a "human voice" in their tweets, the real reason reporters are followed on Twitter is for their expertise and their added perspective of the their beat, says Liz Heron, Director of Social Media at The Wall Street Journal, in this interview with Beet.TV
Also in this interview, Heron gives an overview the first "social Olympics" and how the Journal surfaced the tweets of a number of athletes.
The Journal has been expanding its social media staff, most recently with the hire of Neal Mann, which reported here.