Much like Amazon the iTunes Store suggests things to you that it thinks you might like given your purchasing history. I must say that sometimes I think Amazon knows me better than I know myself, but the iTunes suggestions are sometimes a little wacky.
Take, for instance, the fact that it suggested that I might like Robert Shaw's Sea Shanties (iTunes link), featuring the Men of the Robert Shaw Chorale. Not my usual listening material.
Do you want to know what is even stranger? I took a listen to a few of the tracks, and I bought the damn thing (I'm listening to it now). I am sure my neighbors appreciate hearing sea shanties at 12:30am. I aim to please!