I thought I'd note a somewhat poorly known feature of the Stack Exchange software we're using: when a question has more than 30 answers, so that they're spread over multiple pages, the second and later pages will have a rel="canonical" link pointing to the first page.
This means that only the first page will be indexed by Google.
For example, if you search on Google for this answer, currently at score -1 and page 2, the only result you'll get is a mirror site. (Yes, I know that's not an answer anyone is likely to search for, but I picked it for the example since it has a low score and contains a distinctive string.)
I recently started a thread about this on MSO. Since I mentioned codegolf.SE as an example of a site affected by this feature/bug, I thought I'd post a note about it here as well. Those interested in commenting on the issue in general, as opposed to merely in the scope of this site, should head over there.
I do feel it would be good for codegolf.SE to have this feature disabled here, even if it ends up being kept enabled for other SE sites.
Update: The MSO proposal has been marked as declined. Still, one can at least hope that we might be able to get this feature disabled (and, ideally, replaced with proper rel="next" / "prev" links) locally here on codegolf.SE.
We could perhaps even serve as a testbed for this, to see if there really is anything to some of the more extreme "OMG Google will punish us for showing the question text on multiple pages!" fears voiced on the MSO thread. We've got a lot of multi-page threads here (compared to most SE sites), so if our Google ranking won't crash and burn as a result of this, neither should anyone else's.