It only works on some music

The thing that makes me so unhappy with this is that it ONLY picks up and identifies songs that are on iTunes...Ive used it for several days now and so far it has only identified about half of the music playing (all sold on iTunes) and the ones that it does not identify are easily picked up by the Shazam on my iPad...so something is definitely wrong with the Mac version...and I have a brand new iMac, bought this year, with all the audio sounds set correctly...does this Shazam ONLY identify songs on iTunes? Anyway, Im very unhappy with it...my iPad and iPhone version both work quite well...

qt4suzyq about Shazam: Identify Songs