I know google and Yahoo somehow values different stuff when it ranks websites. Some good tips for Yahoo optimization:

Keywords in URL

alt text

Site Explorer

Prominence

I don't want to copy the whole thing here, but this article explains it:

Yahoo Optimization

Feel free to share your experience of optimizing for Yahoo

I think the best way is to use your key words and site description. Anyway I think there is a large part probability: Will be there a person or ppl who would eventually be interested in searching your topic at the same time (or within a time span), the more the people the better the chance for your topics to be found as the ``crawler'' would do more efforts.

Actually I still cannot find my web site while searching for the included topics...