Actually in certain circumstances it can impose a legal obligation. For example, I'm licensed to sell real estate in California. As a real estate agent, I can create an agency relationship by giving advice in an email. This means that if someone acted on my advice and was harmed by it that they'd have the right to seek damages.

I believe attorneysand CPA's have the same obligation. Unless it is explicitly understood that advice given does not create an agency relationship or something to that effect.