Robert_Charlton - 9:39 pm on May 18, 2011 (gmt 0)
For stories you’ve expanded, you’ll see genre labels for some of the additional articles that explain why they were chosen and how they add value. For example, you might see something labeled as an "Opinion" piece or an indication that an article is "In Depth."
To relate this to Panda results overall... this suggests an evolution of "document classifiers" to another level. In the above examples, I suspect that "opinion" is easier to spot algorithmically than, say, "depth" is, even in a limited universe that's been defined as "news", so I don't think the classification is a trivial task.
While it's likely that document classifiers have been working behind the scenes in refining the algorithm for quite a while now, delivering these genre labels in news would require document classification that works in near real time.
I think that Google uses newly introduced search options and refinements to calibrate its algo heuristics, and the introduction of these particular options suggests another testing phase. There appears to be a run of Panda calibration just starting up in Google's organic results, and that probably applies to News as well.