I know that if I fill in the personal information Opera will auto-complete forms that ask for it. But what I want to know is if by filling in this personal information Opera makes it available to any webmonkey smart enough to extract this info. My guess is yes.
Opera is as lock stock solid as any browser has ever been. The form feature has been around forever in almost it's exact same format (I'd bet it is the same code since it was introduced in 3.2x in 98). I've all kinds stuff in pi forms. No worries - and you know how security concious I am.
I guess I should have been a little clearer. As Brett stated, I don't know of any known vulnerabilities in Opera's personal info section. That doesn't mean there aren't any, or that they're not yet public knowledge, just that I haven't hear it.
PS: With Opera, I'm just a user. Brett is the man.