Having looked at the sites that dominate my area of serps on yahoo and the comments made to me about my site there is but one conclusion i can come to. Do not think about gaming yahoo, you need to cheat. If you are open about everything you do, if its all their on the pages to be seen then you will be penalised by human review. They look at your site for 5 minutes and think oh, i dont like the look of that and youre history. However join the pros with hidden and offpage/site cheating and you are ok. Until they actually ask real users if this site or that site had the information you were looking for, if it was presented in an easier to use form than others sites and would you use that site again then a whole section of innocent webmsters have no chance in Yahoo.