My site has the same thing I have a ton of yahoo slurps on my site before I would hardly get 50 hits in a week now I'm getting like 800.
It looks like about a week ago Yahoo stepped it up a notch. We see the same things in our logs and have noticed Yahoo is picking up squidoo lenses and stuff of that nature even faster than google in many cases. Beyond Yahoo being most accurate with backlinks they seem to be increasing the size of their overall index and like others the traffic we see is increasing weekly.
nah yahoo is very inefficient using hundreds of bots, same is with my site as well, but I never rank with yahoo and it takes months just to get a few pages on there, whereas google it only takes a week to get my pages up and they send just a handful of bots and I rank high.
In one of my new sites Live and MSN started giving very high traffic for a few days. But it went down the same way down.
They are a pain those yahoo spiders, wouldnt be so bad if i actually was high up in their serps lol ! Woc