After Yahoo and Bing merged, my one of site keyword ranking get down in Yahoo. But after continuous off page work improves my site ranking in Yahoo. But still I can't understand what exactly Yahoo's algorithm.
What's the question here? You don't understand their algorithm? How about doing a search on tips to improve ranking in Yahoo.... ?
Different search engine has different algorithm. I think yahoo is now popular in the world and their feature are also popular.
Still continue to do your off page optimization and also if you participate in yahoo answers, you should start now as it would help you for your sites ranking on yahoo.
Well we do rank in Yahoo well, but we mostly target Google for rankings. When you rank on Google well, you have a chance of getting ranked well also in Yahoo or Bing.