False flag? The question revisited ...
Watching the movie Zeitgeist recently I followed a few suggested links and discovered this very sober and well layed out expose on outstanding 911 questions from an architect:
I think if the evidence has any merit it could radically change some folks ideas about what terrorism is or can be.
Anyway I guess it's a hypothesis, the speaker says a real independant investigation needs take place ... says the FEMA and NIST reports were politically comprimised.