One of the themes of my work is how the trend of blogging is impacting law.
One way that this manifests is within copyright. Chris Anderson in his book "The Long Tail" refers to a new approach to how creators feel about their intellectual property and cites these words from Tim Wu, a Columbian law professor.
"What I've called the "exposure culture" reflects the philosophy of the Web, in which getting noticed is everything. Web authors link to each other, quote liberally, and sometimes annotate entire articles. E-mailing links to favorite articles and jokes has become as much a part of American work culture as the water cooler. The big sin in exposure culture is not copying, but instead, failure to properly attribute authorship. And at the center of this exposure culture is the almighty search engine. If your site is easy to find on Google, you don't sue—you celebrate."
Therefore for those thinking about blogging, you need to think less about the law and more about some common courtesy when you refer to others work.