Theoretically, I have tossed around in my head a couple of times since NH, the fact that what may have been going on in the polling there is the classic example of over-enthused Obama voters (driven by the victory in IA) over-responding to polls, whereas the under-enthused Hillary voters under-responded.
Because Hillary had the premiere ground game in NH, her voters showed up in droves, much greater than their poll numbers indicated, while Obama's people (who had the lesser ground game) were relying on the Independents, who, as JJ mentioned, went right back over to the Republican side where they normally voted.
If so, that is the likely validation of the second rule, I suspect. Or maybe ground games really do count.