Now, I know that it's mainly a money move, but I find it funny that the two sequels have been contending on the calendar like this, considering that Saw 6 director Kevin Greutert had briefly stepped away from that franchise to potentially helm PA2 until Lionsgate legally obligated him to finish the series off.
Their returns had been declining since the first sequel, with Saw 6 grossing half of what its predecessor had. (I know that I skipped out on that one in theaters.) The solution? 3D! As for Paranormal, it's either still being shot on the quick and quiet or (more likely) already in post-production by now, and as far as the Craven is concerned, well... we haven't seen a trailer or a poster yet, and since it's also in 3D (converted in post, ugh), it could shuffle off to a different date in an effort to snag some screens.
Oh, Jigsaw -- maybe the box office is your biggest trap of all.