[gamblor956]

No, a preexisting attorney-client relationship isn't always required. Offering advice pertaining to the application of laws or regulations to a specific person's facts is generally considered offering legal advice.

Some states regulate this very heavily, others don't care as much. Generally, California tends to regulate this pretty heavily for lawyers (for purposes of creating an attorney-client relationships that can subject them to malpractice claims) but otherwise not at all for non-lawyers unless they specifically hold themselves out to be in the business of providing legal advice (very common with immigration issues). So, offering random advice on the internet wouldn't be an issue for a non-lawyer (but could be one for a practicing lawyer if they get too specific).