I, too, was wondering what Baiku meant as I have seen it used numerous times on this site. I Googled it and one guy claims he invented it and it is a Bi-haiku type poem because it uses six lines instead of just three, so he named it Baiku. However, another guy claims it is writing Haiku poetry while riding a bike. Hard to tell what the real story is here, but I am leaning with the double Haiku theory.