aristotle - 6:27 pm on Mar 24, 2012 (gmt 0)

What might be accidental "low-quality signals"?

If people don't like it, they don't bookmark it, they don't print it out, they don't explore other parts of the website, and they don't come back. Those are examples of "low-quality signals". And I would bet that they cause a lot more ranking problems than any "accidental" signals.