Alexa is not a valuable ranking system because they require downloading their "tool bar" which most (intelligent) people would never do because it is just more overhead for an unnecessary task.
Quantcast, however is gaining huge momentum in the industry to the point even Nielson is looking at their technology (and everyone knows Nielson needs help!).
ATS has achieved the sub 2000 rank on Quantcast all by itself
Very nice...
Springer...
Springer...

