It is alternate spelling for Bitch for people who either are on online games that will not let you say cuss words (Ex.Metrowars or Kingdomofriches or Runescape.) Or for moronic people who dont know how to spell correctly.
Ex 1. Oh dam I lost to that rat! That Bytch!
Ex 2. happywithluv: that bytch had no rite to be up in mi face