YouTubers test out Ghost Radar, one of the most popular mobile apps for detecting "ghosts." WSJ's Andy Jordan samples the online amateur reviews.

For one, you can flip through a selection of Ghost photos and watch a few ... for the tech-minded out there, and the app will also help you find the closest Rolls-Royce dealer.

Ghost hunters Roger Pingleton and Jill Beitz, founders of StreamSide Software, have developed an iPhone app they say gives the dead a voice. In developing the Spirit Story Box app (99 cents to ...