A blog search feature has today been added to the Ask.com search engine. This makes Ask.com the latest of the major search providers to create a service specifically tailored for finding information on these popular online journals.

To create the index for its new Blog & Feed Search, Ask.com analysed the subscriptions of the hundreds of thousands of users of its Bloglines service, which it acquired in February 2005.

Bloglines is a free, web-based RSS reader that people can use to subscribe to syndicated feeds from their favorite blogs. Ask.com had said in the past that it planned to integrate into its search engine features from Bloglines, including the service's search engine, which from today will also have had a makeover.

The Ask.com blog search index features about 1.5 billion posts and 2.5 million content feeds, as well as a sub-index of news articles from about 7,000 sites.

Ask.com argues that by using Bloglines subscription data to populate its index, as opposed to the more traditional method of blindly sending a robot to crawl websites, it will be able to deliver more relevant and higher-quality search results.

In addition to factoring in how popular a blog is based on its Bloglines usage, Ask.com also mixes in its algorithmic search technology to solve queries.

The service lets users search for actual posts, feeds or news, and sort the results by relevance, date or popularity. On the results list, Ask.com also lets users subscribe to feeds or clip a search result, both via drop-down menus located below each result. Ask.com gives users not only the option to subscribe or clip to the Bloglines service but also to other competing ones.

Users can also subscribe not just to a feed from a specific blog but also to a search query and be notified via their RSS reader whenever content matching that query is posted to blogs monitored by Ask.com.