I enjoy Felix Salmon, even though I don't always agree with him.
He wrote an interesting post about biking, which while somewhat specific to NYC (where salmon are truly an epidemic, instead of the occasional nuisance they are here), is a worthwhile read
While many of the commentators (and I as well) disagree with him about lane splitting-AKA filtering, the thing that is interesting to me is the idea of bikes using a pedestrian mindset, and therefore drivers not being able to process bikes as a third category.
After a day to think about it, and leisure to re-read it more thoroughly, I agree with the entire article until it gets to the "update" and the comments. Although the comments are much more intelligent than your average bike story, I think that Felix is wrong about insisting that bikes must keep to the far right and not "impede traffic". NY State law as quoted in the comments is actually quite progressive in that is specifically addresses a lane too narrow to safely share as a reason not to ride to the far right, but still he asserts that it's the duty of the cyclist to stay right.
If you're a regular here, you know how I feel about "filtering", but I have to say based on my very brief Manhattan cycling experience- lanes on the big avenues are wider than in Boston, so it's safer to filter, and it's safer to "lanesplit" and allow cars to pass in the same lane, so it might be a context sensitive debate.