How blogs help build a reputation

Steve Rubel cites Kevin O'Keefe on how blogs can enhance one's reputation as a trusted and reliable source of information in as little as 3 to 6 months. O'Keffe writes "Within a month I had lawyers from all over the country calling me on Internet marketing issues and asking how to publish a blog and if I could help them. That’s lightening speed for getting my name out."
Of course, the more bloggers there are, the greater the impact of any one voice may be diminished.