Well, OK, Jopr won't let you know if there is a cherry bomb strapped to your laptop, but, it can alert you if something is physically wrong with your hardware that may cause it to malfunction, assuming your hardware can provide Jopr with relevent data.
Take for example, the premature ending of Greg Hinkle's Jopr demo a few weeks ago. Greg's computer crashed for what seemed like an unknown reason - but because he was running Jopr on his laptop (which had his experimental hardware plugin deployed), he was actually able to use Jopr to figure out what the problem was. Turns out, his laptop was slowly overheating - which ended up crashing his box. Check out his blog to see what the graph looked like.
Too bad he didn't have any alerts set up on the temperature metric - he could have received an email from Jopr telling him his machine was about to blow up because his hardware reached 100 degrees :)