Throughout the years I've heard those not from San Francisco call it Frisco and I've always cringed, knowing the people SF hate that. Well, here is the official word of caution from the SFGate's Visitors Guide. Consider yourself enlightened.
It used to be that if you referred to the City (the preferred term for San Francisco) as Frisco, it signalled you as an ignorant rube. In the last few years, though, there's been a small and quiet revolution underfoot to liberate it as a term of endearment. However, saying "Frisco" when referring to San Francisco has not yet achieved mainstream status, so a good bit of advice is this: don't use "Frisco"...
