Hello,
On my site (www.bridgman.co.uk) we had a lot of duplicate page issues as reported by the Seomoz site report tool - this was due to database driven URL strings. As a result, I sent an excel file with all the duplicate pages to my web developer who put rel canonical tags on what I assumed would be all the correct pages.
I am not sure if this is a coincidence, or a direct result of the canonical tags, but a few days after (yesterday) the amount of pages indexed by google dropped from 1,200 to under 200.
The number is still declining, and other than the canonical tags I can't work out why Google would just start de-indexing most of our pages.
If you could offer any solutions that would be greatly appreciated.
Thanks, Robert.