For me, it was because I download random things all the time. At that time, the only Shiina song I had heared was her duet with Utada Hikaru,
I wont last a day without you. I hated it. I still kind of do. Being extrememly biased, everytime someone mentioned her I would immediatly say I couldnt stand her. In some forum, a person uploaded "Kyoiku" from Tokyo Jihen, and I had no clue it was her band. I'll be honest, I thought it was like some middle aged woman who smoked a lot >_> But for some reason I still loved the sound of it.
I was terribly surprised when I looked them up on Wikipedia and found outshe was the vocalist
Ever since I've been listening to her music, and I absolutely adore her voice and her talents as a songwriter/composer.