Why are my AutoFill and Password not Working?

Since recently upgrading to Mountain Lion and Safari 6, the AutoFill and Login/Password functions only work sporadically. A few sites use the login/password function while most sit there with blanks and never ask if I want to "Save This Password." I am repeatedly ask for email address and never see options as I start to type. Most forms do not fill as I start to fill them ?????

All this worked like a charm in the previous OS.