Vid, today for me was especially significant because it "reveals" and "confirms" how the shorts are handling the increasing demand for Ariad shares. We have been theorizing in the dark for so long about the ups and downs and the increase in short interest in light of the rise in pps shows their hand...big time.
The action on level II is the same pattern, except now the ante is UP because instead of the shorts trying to control the pps with 100 share trades, it is now up in the 2,3,4000 range. What I also see on the ASK side are what look like "real" sellers lining up and then disappearing (not selling) at the last second thus playing with the short tactics of jumping the ASK line with lame low volume selling at a lower pps (at least trying to). I am not sure how that all works but it is a difference that I have noticed and perhaps one of the reasons why the pps is holding UP.
Of course, NOTHING is as good as longs accumulating and with that there are less and less cheap shares to buy.