Google launched Blog Search in September 2005.
There are two versions, one with the standard Google interface and one with the Blogger interface. One major difference from the standard Google search is that you can sort the results by date, making it easier to find recent posts instead of ones the standard search deems most relevant.
Four new search operators can be used with Blog Search:
In mid-September, Google launched a new search engine: Google Blogsearch. The new search engine, whose development was announced over two years ago, allows you to search blogs by dates, date ranges, language, authors, and by the blog itself, in addition to keywords. It is then possible to set up your own custom newsfeed with these search criteria.
Despite the features, there has been criticism related to this new engine. One example is how their index only dates back to March 2005. In addition, flaws in the search algorithm may result in duplicate blog entries, as well as other "blog noise" to receive high results.
This new search engine was made supposedly to help compete with other search engines, such as one by Yahoo!.
Google Blogsearch has joined the group of other Google search engines, including Google Image search, Google Groups, and the famous Google Web search.
According to some LiveJournal posts, Blog Search is ignoring robot policies and indexing pages it shouldn't.
It seems too temperamental at the moment. A search for "Track the most recent changes to the wiki" gives no results, but if you search for Special:Recentchanges, that text is there. Since it's searching anything with an RSS feed, there are a lot of wikis in there, not just blogs.