Please consider a list of items (forum comments, articles, shoes, doesn't matter) which are spread over multiple pages. Different sort orders are supported (by date, by popularity, by price, etc).
So, an URL might look like this (I use the query style here to simplify things):
Now, in terms of SEO, I think I should be worried about duplicate content. After all, each item appears at least as many times as there are sort orders.
I've seen Matt Cutts talking about the rel=canonical link tag, but he also said that the canonical page should have very similar content. But this is not the case here because page #1 in a non-canonical sort order might have completely different items than page #1 in the canonical sort order. For a given non-canonical page, there is no clear canonical page listing all the same items, so I think rel=canonical won't help here.
Then I thought about using the noindex meta tag on all pages with non-canonical sort order, and not using it on all pages with canonical sort order.
However, if I use that method, what will happen with backlinks that are going to non-canonical pages -- will they still spread their page rank juice, even though the first page googlebot (or any other crawler) is going to encounter is marked as "noindex"?
Can you please comment on my problem and what you think is the best solution?