I don't think we'll every know for certain. Both Yahoo and Google are pretty secretive about the exact way their search engines work and rank things. I just keep working on basic SEO and hope for the best.
Using the same seo methods to optimize bothe Yahoo and Google might work but about their algorithms, no one knows for sure but they are both different.
true... however, I've noticed that for instance yahoo pays more attention to web domain than google. a website which contains the main keywords in the domain name will be ranked on the first page very fast: this doesn't happen on google
Google's algorithm seems to be more complex, which is capable of taking into account of various qualitative factors of a website's content. Yahoo's algorithm assigns a bigger weight to link popularity so it is easier to manage the search result rankings on Yahoo. But Yahoo's search traffic is just a small fraction of that of Google so you might find that a higher ranking on Yahoo still generates much lower traffic than Google.