Morisette all but outright confirmed it was about Coulier on the Stern show.
I believe Artie Lang summed that up best when he said, "What'd he do, impress you with his Popeye impersonation?"
Ya know what though, Bob Sagget's stand-up routine is really funny (IE: Not cutesy, but rather vulgar and "adult"), and I've heard Coulier's pretty funny too. They were molded into the tools they're more commonly known to be though.
I've seen Sagget's routine, and it is good. Seeing it and knowing who he played on TV makes it even funnier. It's like old P.W. and his "adult" comedy special on Showtime/HBO, and yet comparing his TV show with it. His films were then more a happy medium of the two "sides".