I'm not sure what the demographic is (and I'm too lazy to find out) of those TV crime procedurals like CSI and Law & Order, but I'm going to guess that it's a bunch of old ladies. My late grandmother watched these, as does my mom, so I'm pretty sure my guess is a good one.
Untraceable is a serviceable thriller (the trailer moves way faster than the movie does) that unfolds like, say, an episode of NCIS, but it includes scenes of torture (a man blisters and burns to death under heat lamps, etc.) that give the film its "R" rating—which means that old ladies must like torture too, not just those young kids who've made the Saw franchise so successful.
The twisted psycho in Untraceable tortures victims and streams his antics live online. The more people visit his website to watch, the faster the victim dies. The film gives a sort of pedestrian commentary about cyber culture and our delight in the suffering of others (after all, we bought a ticket to Untraceable, didn't we?).
The torture scenes are not nearly as graphic as those other horror movies of late, which means old ladies won't be sent into cardiac arrest while watching.
On a side note, I know that half this blog's readership finds no thrill in the ogling of certain lithe male celebrities that get touted here again and again because you all prefer hunky men who cannot be mistaken for menstruating girls.
Well, ladies (and some gentlemen), I give you Untraceable costar Billy Burke. He's been in a bunch of movies and TV shows (I remember him from 24), and he's an unmistakable hunky piece of man meat. Don't say I never attend to your needs too.