Sourced From SearchDay

Google has introduced its long awaited blog search service, becoming the first major search engine to offer full-blown blog and feed search capabilities.It’s been nearly two and a half years since Google purchased Pyra Labs , the company that built the hugely popular Blogger publishing service, and Google has been promising blog search ever since then.

While Google web search has allowed you to limit results to popular blog file types such as RSS and XML in web search results for some time, and its news search includes some blogs as sources, Google hasn’t had a specialized tool to surface purely blog postings. In fact, while all of the major search engines have been dabbling with blog and feed search, none has done much with blog search until now.

Google’s new service (in beta, naturally) is available both at and . Google blog search scans content posted to blogs and feeds in virtually real-time, according to Jason Goldman, Google product manager for blog search.

“We look for sites that update pinging services, and then we crawl in real-time so that we can serve up search results that are as fresh as we can,” said Goldman.

Google defines blogs as sites that use RSS and other structured feeds and update content on a regular basis.

Although Google Blog search focuses primarily on content published to the blogosphere, it’s not a true full-text search across all sources, according to Goldman. This is because some publishers only syndicate excerpts of content via RSS. Google’s blog search indexes all of the content it finds in feeds, but does not attempt to access and index the full content available on a publisher’s web server.

Google does use information garnered from its crawl of the web to identify potential blog sources, looking at meta data, links and other clues that might point to a feed. However, Google also respects the robots.txt protocol, and will not crawl any content that’s disallowed by a publisher.

Google blog search results point primarily to individual blog postings, with a title and snippet from each-strongly resembling Google’s web search results. In some cases, links to “related blogs” are presented at the top of search results if a query suggests that the user is looking for a particular blog rather than a specific blog posting.

Results are sorted by date, with recent posts appearing at the top of the list. You can also choose to sort results by relevance. Goldman says that while blog search uses its own unique approach to relevance ranking, it also draws a lot from Google’s web search ranking algorithms.

Google blog search has an advanced search page and a number of commands are available. allowing you to limit searches by title, author and date or date range. You can also limit results to a specific language, or apply the Safe Search filter to results.

You can also discover who’s linking to a post or blog using the link: command. Unlike Google web search, which sharply curtails the number of results displayed using link: command to discourage abuse by search marketers, the link: command in blog search displays a comprehensive and nearly complete list of sources linking to a particular post or blog.

You can also save a blog search as an alert that gets updated any time new content is posted matching you query. Google blog search allows you to issue a query and then subscribe to that query via your RSS feed reader, with either 10 or 100 results being displayed.

Goldman says that Google is not including news sources in blog search, except in rare cases, so there’s little overlap between Google News and Google Blog search.

Google is not offering any means of submitting a blog or feed to the new service. However, if you publish a feed and want to include it in Google blog search, the easiest way to make sure it’s included is to make sure your publishing system is set up to notify popular blog pingservers that are monitored by other blog search services. The easiest way to do this is via pingomatic , which can ping more than a dozen popular pingservers, according to Goldman.

Google Blog Search is available in English as well as Brazilian Portuguese, Dutch, French, German, Italian, Korean, Russian, and Spanish, with additional languages promised soon.

For more information, see the Google Blog Search FAQ .

Now that Google has launched blog search, expect the other major search engines to follow suit fairly quickly. All have been feverishly working on blog search over the past year, and now that Google is first out the gate the others will likely move quickly. I’ll circle back and take a closer look at blog search once all of major players have launched their services, most likely by the end of this year.