I didn't see a link to the old seo catalog on your site, but just in case I missed it and you are using it, something to bear in mind. Of course, if you aren't using it, ignore everything that follows (IMG:
http://forums.networksolutions.com/style_emoticons/default/smile.gif)
we didn't wait for NS to do our V4 migration as their timeline didn't work for us, so instead we opted to sign up for v7, recreate the store and then do the switch.
we knew the seo catalog was defunct in v7, and many had stopped using it way before v7 was announced, but we kept it going. when we knew we were definitely going to v7, we removed the link from our site to the catalog and turned it off.
nothing changed for about 3 months, but then boom. End of Sep 08 and we got slapped with a -50 penalty right across the board from Google. Traffic dropped about 90% overnight and it took 3 months just to get the -50 lifted and when it did, many of our rankings didn't recover. it's taken over 9 months, a lot of money and effort to get our rankings back.
the reason?
in short, the de-indexing of all the seo catalog pages was to much of a dramatic change for G, hence the penalty. G saw it as we had lost 50% of our site, when it reality we hadn't.
so if you can, make sure you 301 as much of that seo catalog as possible, we didn't.
if you want a more specific explanation as to why we got the -50, just let me know.