Some questions:

1. You only have changed your host or you made any other on-pages changes, like title tag, etc.

2. Your unordered lists are incorrectly marked up, which breaks the semantics of their content, and since Yahoo cares more that ever about the appropriate implementation of semantical elements, could be that has affect you.

I am sure we will figure out what is going on.

__________________
"Being an expert isn't telling other people what you know. It's understanding what questions to ask, and flexibly applying your knowledge to the specific situation at hand. Being an expert means providing sensible, highly contextual direction." Jeff Atwood
SEO Workers - Search Engine Optimization Consulting Company | SEO Analysis Tool | Webnauts Net SEO