vbulletin integration suggestion and facebook
 

When vbulletin finally gets the software up to par to allow us to put the CMS at the root, the forum at forum.mysite.com the blogs at blogs.mysite.com, it would be nice if we can get the reviews in a subdomain yet still have it integrated properly. I guess you'll need to see the final code before deciding but I would definitely love that addition.

Also a facebook like button for the product would be nice too.

the software already supports subdomains and has since it was created

Read the cookie tutorial in the FAQ forums and your cookies need to be set like that for them to work with subdomains.