Google launched its highly anticipated Blog Search engine today, with Yahoo and MSN expected to follow shortly. The need for industrial strength searching capabilities for blogs has been obvious, given the explosion of blogs in the last two years. The specialized blog search engines simply didn't have the resources to handle the sheer number of individual publishers and the amount of user generated content being generated by today's bloggers. Interestingly, there are two different URLs: google.com/blogsearch with a Google style interface and search.blogger.com with a Blogger style interface, showing the integration with Blogger.com for content creation.

The creation of a separate Blog Search shows further development of Google's maturation into a more sophisticated search service with updates and search options tailored to the type of data. According to the Google FAQ, the mechanism for including blogs is through standard ping services and RSS, which provide more timely updates than the crawling mechanism for the main web search. While the first search option is the usual white box, the advanced searching options reveal new search options unique to blog content: author, since blogs are created by individuals; titles, similar to an article title, date created and URL, which could be considered the equivalent of a publication name.

Websites in the main Google search engine have a PageRank, which is based on link references. However, relevancy for blog content is heavily dependent on "freshness", and the algorithms for determining relevance are substantially different for typical short postings found in blogs. Sorting of search results by either date or relevance is a very useful feature. Overall, Google Blog Search is a welcome addition the search world, and should make the chore of monitoring sentiment changes more doable.