No, it's not a technique used by teenagers hoping to grow a mustache and or beard to impress their (frequently imaginary) girlfriends . . .It's for those on the Mac side who want to measure their speakers. I'm looking into it, but since I have a PowerBook which lacks line out, I'll have to do a bit of adding on. It can take quite a fine sample and turns out great looking graphs from the looks of the web site.
Usual disclaimer: I have no connection to Fuzzmeasure; in fact I never heard of it till last week, and haven't actually used it yet, but the results from thos who have look pretty spiffy!