The Daily Advertiser, which is based in Lafayette, Louisiana, has an article on how blogs are changing political discourse:

Ben Domenech, a former Bush administration intern who launched the conservative RedState.com, was dumped in late March as a blogger at Washingtonpost.com after liberal rivals unearthed plagiarism in his work, triggering a flurry of Internet commentary, known as a "swarm."

Then late last month, the Los Angeles Times suspended columnist Michael Hiltzik's blog after a conservative critic exposed Hiltzik's practice of using pseudonyms to post provocative comments on other blogs.

It's probably a combination of these polticially-charged times coupled with blogs' ability to act as an amplifier for word-of-mouth, which was traditionally had the same limits as your ability to physically travel. Your blog speaks for you even when you're asleep, and thanks to the fact that search engines rank them highly (since search engines "feed" off links and blogs are an excellent source of them), it's considerably more "findable" than you are.

The article has a list of politcal and news events in which blogs have played an important role:

Recent episodes dramatize how swiftly and powerfully they may react, sometimes rivaling mainstream media in their ability to track events and connect the dots in real time, and influencing traditional news coverage. Consider:

• Blogs applied the pressure that led to Trent Lott's 2002 resignation from the U.S. Senate after making what some construed as racist remarks.
  
  
• It was a blogger dubbed "Buckhead" who in 2004 exposed forged documents used by CBS News and Dan Rather in stories about President Bush's National Guard service.
  
  
• Former Sen. Tom Daschle, D-S.D., was unseated two years ago after conservative bloggers attacked him and forced the state's largest newspaper to modify its coverage of the race.
  
  
• Blogs raised early questions about the Bush administration's handling of the Hurricane Katrina crisis. A study by Loyola University Chicago sociologist Lauren Langman concludes that the blogs forced critical mainstream news coverage that weakened support for the president.
  
  
• Last year's U.S. Supreme Court nomination of Harriet Miers was withdrawn after conservative blogs derided her qualifications. Bush took the unprecedented step of holding a conference call with the bloggers in an unsuccessful attempt to quell criticism.