When you write your CV, what do you count as an invited talk? Does it count if you're invited but not provided funding (this has happened to me several times at AMS special sessions)? What if someone runs into you in the hallway and invites you, but never sends you a 'formal' invitation email? What if you're a PhD student and your advisor asks you to give a talk in the department seminar or in a conference they are organizing?

Also, does it even matter? What if I just put a section in my CV called "talks" and not worry about the distinction?

Thanks in advance!