Hi Dave
I’m no expert here but I believe Yahoo, like Google, keeps their algos fairly close to their chest for obvious reasons. WMW has an excellent Yahoo specific forum (among others) which is worth looking through as this update is under discussion there.
My initial thought was that maybe you were linking to the casinos with aff_tags but you’re not, you redrect thru your own script. I’m pretty sure they don’t penalise sites for being casino/gambling related as i have one or two high SERPS in niche terms.
Cheers
Simmo!