When I first launched my site, it I had MediaWiki in the root and a wordpress blog in a subfolder, /blog/.
After a while spammers took over the MediaWiki site and I had to remove it. The problem is I lost a lot of good content and inbound links from 3rd party sites.
My goal is to redirect the root folder to /blog/ while keeping the rest of the URL string intact. I have a Wordpress plug-in going that will automatically track the 404 errors. As these come in I'll be able to pull the old content from archive.org and give it a new home on a wordpress page.