Recently, I migrated a client's site to a new server and a new home within WordPress so they could more easily edit their website and start a blog section.
The static site was 10 years old a was showing up at place #3 for it's primary keyword, consistently, according to my client, and has dropped to rank #6-8 following the migration.
At launch, we made sure the urls were identical (save the removal of ".htm" which we used 301 redirects to compensate for) and we generated a new XML map and pinged Google with the new site. We keep a 404 log to make sure we're not losing any incoming links.
We also have Google Webmaster Tools on this site and have zero errors/suggestions, everything seems OK.
I was told by numerous sources that Google would not penalize us for the use of 301s, but it's the only thing I can think of right now that is different about the site, other than the platform.
Any ideas about what we could be getting docked for?