When I have been there in the audience to see him hosting "Late Night, " I can't help myself: I still look for the ghost of Johnny Carson in the house, and of myself there years ago as a child.

WSJ: Remembering a time before 'Tonight' left New York

"Pepper's ghost" isn't the sort of phrase you hear very often at a show like SXSW. In amongst all the latest generation technology, there aren't too many folks discussing hundreds years old optical concepts.

ENGADGET

Okay, the fact that we're all walking around with video cameras has increased the statistical likelihood that we'd finally catch a ghost on camera, and in doing so we decrease the likelihood that they exist every day we don't catch Casper.

ENGADGET: This is the Modem World: So where are all the ghosts and aliens?