Today's new Web Law Connected column on SLAW by Steve Matthews, "Thought Leadership - A Long Term Investment" talks specifically about this, and how it relates to the legal professional. He says:
The concept of Thought Leadership is hardly new, of course. Lawyers have become experts off-line in their fields for years. There are, however, a number of characteristics that are unique to the online space. First of all, the barrier to entry has definitely been lowered. While web technology has been limited to those with programming expertise in the past, newer software technologies - such as blogs and social networks - have leveled the playing field for exposing one’s professional knowledge & expertise. Second, the number of participants in these online conversations is not limited. Those with a willingness to get in there and participate will benefit from the increased exposure. And lastly, the web is a mix of both those that innovate ideas, and those who diligently spread the word.
Someone truly web-savvy can leverage an online presence into a higher profile and name as an expert. The trick is learning how to accomplish this by using and experimenting with the new media tools.