At the risk of propagating a dubious cliche, here's how I'd characterize Industrial Metal (wikipedia, allmusic):  Whereas other Metal bands started with a couple of headbanging outcasts jamming in a garage, Industrial bands started with a lonely outcast fooling around in his room with a guitar, drum machine and sequencer.  To put it another way for the complete Metal neophyte, Industrial Metal is what you get when you cross, say, Moby with Metallica.  For whatever reason, this is the one subgenre of Metal that I kind of managed to keep up with during my anti-Pearl-Jam-and-Nirvana, Swing-Music days.  Don't be fooled, however; Industrial is much more Metal than it is Club Music, and its gritty, dark tone belongs right there with the other subgenres.  As you can tell by all the s, I'm a big fan of Industrial Metal!