The term Blog is a portmanteau of the words 'web log'. Originally the term was used to describe online journals or diaries of people's daily lives, but the use of the term has expanded as so-called 'bloggers' have become independent sources of news (e.g. Informed Comment and Truthdig) and narrowly-focused online commentary and review (e.g. Gizmodo, Autoblog or Boing Boing).
Additionally, blogs have become a source of "new journalism" - many prominent newspapers, even the New York Times, have created blogs, especially to cover continually evolving issues like political campaigns.
Conservative and libertarian blogs have been useful in exposing the mainstream media's lies, blackouts, liberal bias and the Clinton and Obama administrations. For example, a popular Pat Buchanan fan blog propagated a leaked video of a CNN Gulf War report, which claimed to be live coverage from Saudi Arabia but was actually a staged performance with props.. The blog WorldNetDaily is known for its work on Barack Obama's birth certificate and pro-Islamic tendencies. Ron Paul's 2008 and 2012 primary campaigns have benefited from fan blogs such as Daily Paul.
Politics and the Blogosphere
Law professor Ann Althouse said: "I have found that people on the Right are much more likely to link to me, write about me favorably when they agree with something, and just ignore what I am saying when they don't agree. It's the other way around on the Left. ...My experience in life generally is that people on the Left think you are evil if you don't agree with them, that you're actually a bad person..." 
- Blogging While Female Part 2: Five Women Bloggers Talk About Gender Issues And The Blogosphere, John Hawkins, Right Wing News, March 18, 2008