If you're searching the Internet specifically for blog posts, Google's basic search isn't the best way to do it. Not only will your results be cluttered with non-blog pages, they'll will be skewed toward sites like The Huffington Post that have figured out how to win at search engine optimization to get to the top of Google's results. Google Blog Search is a much better tool for the job. It lets you sort results by a relevance score, or sort by date to display the newest posts.
But there are other blog search engines, each of which has a particular strength, according to ReadWriteWeb writer Marshall Kirkpatrick. He's created a chart of five blog search tools that shows which to use for what. Technorati, for example, has an option that filters out posts from blogs that aren't widely linked, so your results won't be cluttered by spam-laden blogs that use content scraped from other sources. These "splogs" are designed to display ads to surfers who unwittingly click through to them from search engines.
Most important, Kirkpatrick found that no one search tool found every blog post on the Net. IceRocket found posts that Technorati missed, and vice versa. If you're looking to find everything being said about a topic, you need to hit them all.