BOSS (Build your Own Search Service) is Yahoo!'s open search web services platform.

http://developer.yahoo.com/search/boss/

http://www.techcrunch.com/2008/07/09/yahoo-radically-opens-web-search-with-boss/

Good move. Though, Yahoo always had a search API and this seems just a new name for it, with the following changes according to the BOSS page (technical changes aside):

- no more queries per day restrictions
- you are allowed to reorder results, and mix and mash with your own content
- you are allowed to use it commercially, and without attribution

None of these were big issues with the existing Yahoo Search API in my past tries though... And I bet even in the past people reordered the results, displayed ads, not always mentioned Yahoo etc...

Thanks for the clarification, Philipp. :)