Google Blog Search is a weblog search engine, with a continuously-updated search index. Results include all blogs (including foreign-language blogs), not just those published through Blogger. Results can be viewed and filtered by date or users can browse results by topic.
An "Advanced Search" link allows users to specify titles, authors, languages and more and has an additional link that allows users to switch between displaying the results with either the most relevant or recent results at the top.
Blog Search uses a set of algorithms to try to determine the most popular stories in the blogosphere. Factors considered include a blog's title and content, as well as its popularity throughout the rest of the blogging community. Groups of posts that are closely related are also displayed. The process is entirely automated.
Blog Search indexes blogs by their site feeds, which are checked frequently for new content. This means that Blog Search results for a given blog will update with new content much faster than standard Web searches. Also, because of the structured data within site feeds, it is possible to find precise posts and date ranges with much greater accuracy.