DanAbbamont - 10:43 pm on Apr 16, 2011 (gmt 0)
I'm definitely under the impression that it has a whole lot to do with the ratio of thin pages to actual content pages. That Digital Trends site has 34,000 tag pages and 33,000 actual articles indexed.
Cinemablend just recently made all their results pages canonical so we can see if that was it.
Techradar has tags / different sorting / pagination going on all over the place too.