tedster - 1:58 am on Aug 23, 2011 (gmt 0)
I fully agree. Here's how I see the connection. The issue with large websites is having enough PR to make it seem worthwhile to Google - that and having a good link structure. The problem with canonical errors is that they sap Page Rank, and they cause googlebot to give up indexing.
That's why I added a post about canonical advice. If you've got a plug-in, adding canonical tags can be a relatively easy thing to do - and then you've got easy insurance against one potential area of nasty trouble.