I have about 50 different topics (and over 5000 pages) and the one search engine I never really systematically submitted my sites to was Yahoo. Hence my results for the key terms used by my visitors used to be pathetic. See:
http://www.findians.com/focus.html
With my test of the new search engine most of my sites appear as an absolute No. 1 and all my key sites are in the top 20, and usually well within the top 10.
However, I will have to test the aspect of the speed at which my updates appear to come in the top 20 sites.
I have maintained my top positions in Google with no problems with most of my subjects, but the new Yahoo even betters my positions in the ones where I had lost ground in Google.
Secret of success - never do anything to get a placement on Search Engines and never pay for listing. Keep to the subject of your web pages!!!