I've got a new criterion for Bin Laden tapes. No audio tapes will be considered real. Any Bin Laden tapes must show video as well as audio, or they will be considered inauthentic. I don't know why our government isn't already doing this.
It's an easy thing to crank out a poor-quality tape and say it's Bin Laden. However, anybody could be impersonating him.
I personally think he's dead, which is why we never see him anymore. Remember, he was very very sick the last time we actually saw him on tape.
Any threats, of course, coming from audio tapes will be taken seriously. However, we will not assume that they come from Bin Laden himself, but from his rabid followers.