Yahoo announced today that it has added Blog Search (in beta) to Yahoo Search BOSS, the company’s “Build Your Own Search Service” open search and data platform.

“Developers looking for a blog search API often find the APIs that do exist are providing a variation of a web index,” says Rahul Hampole with the Yahoo Search BOSS team. “We decided to take a different approach. Yahoo! developed a custom blog index where the relevancy is specifically tuned for blogs. This allows us to provide you a wealth of data such as the provider, the author, date of post and in certain cases, contextually relevant terms associated with the article.”

“By their very nature, web indices used for blog search cannot provide the complex functionality that developers demand,” explains Hampole. “For example, try finding a commercial API that will give you all the blog articles written on ‘Yahoo’ in the last week sorted by date. Yes, I know, I couldn’t find one either. Developers can now make that exact query on BOSS and build a rich powerful application. As always, BOSS developers get maximum flexibility on the display of this data.”

Yahoo has set the pricing at ten cents per 1,000 queries. Users can apply to show advertising when they sign up, and those who have already signed up for BOSS can use Blog Search immediately.

Yahoo says it has hundreds of developer sites using BOSS for millions of queries each day. ” We have seen fascinating applications in social, mobile and on the web that are using the service,” says Hampole. “Our goal is to nurture and grow this ecosystem by continuing to add new services and helping you monetize your offering.”

He says the team’s next goal is to “shake things up in mobile,” adding that they’re not planning on a BOSS OS.

Earlier this year, Yahoo launched BOSS v2, which brought a number of new things to the table (including Yahoo Search advertising).