hey, do you have a robots.txt file? Maybe this is just a rumor, but I heard that there is a better chance for Yahoo to index your site if there's a robots.txt file. Also, make sure that you have meta tags. Inktomi's Slurp is the only major search engine that still uses meta tags. Submit your site to their search and directory also. You can find the link to the search submission here:
One of our sites that was in top 10 for almost 7 keywords with a competition of nearly 39,300,000 pages is gone from Yahoo. It is not even listed for any keyword. The site seems to have been removed after this update. We never did anything wrong.
How is that possible and how to request yahoo for it's re-in-inclusion?