Variant of "Shimano", top Japanese company which makes bicycle components (from groupsets to wheels to pedals to shoes). Akin to Microsoft in its pervasiveness and near-monopoly of the market (at least as far as groupsets (chainrings, cranks, bottom brackets, shifters, cassettes, etc)) and certain mediocrity, it is found on many bikes from the cheap low-end models to the nicer ones which actually aren't too bad (XT, XTR, Ultegra, Dura-Ace) but cost a grip. There are alternatives, at least for the groupsets - Campagnolo (go Campy) and SRAM (Sachs).
Look at that damn roadie's Bianchi - full Campagnolo gruppo! <drool> (looks down at lowly Shitmano Sora groupset).