Jon12345 - 12:05 pm on Aug 20, 2012 (gmt 0)
I have just checked a site of mine, which is composed of WordPress for main site and vbulletin for the forum. The forum has over 1 million posts.
The WordPress section has a canonical redirect, but I have just noticed that the forum doesn't. The home page is PR4 and the forum home page is PR4.
How big an impact is it likely to have by setting a canonical redirect for all the forum pages?