That mountain of bids at $4.47 and $4.45 right now looks rather impressive. Someone with a lot of cash doesn't want bitcoins to fall much further (than they already have). They really put a floor underneath the falling market. Will it hold?
Or maybe some early adopter is trying to sell off the rest of his stash?
If you sell into this wall and he was serious - it bounces and you are the sucker.
If you buy his last stash of bitcoins and he pulls that floor from under your feet - bitcoin crashes and you are the sucker.
Risky business.