So D is trying to fix my very unwell computer while I curl up on sofa under a blanket and blog. Sounds about right :) The topic: charisma. Everyone knows what it is and most can usually agree on whether any given person has it... but how to define it?
warmth...?
cheerfulness, positivity...? it's hard to imagine a sourpuss/Debbie Downer being charismatic. Hm that's a surprising one - haven't thought of it before. *makes mental note to be more positive, dammit*
...the ability to talk interestingly...but what does that mean? - in a way that is somehow unusual or distinctive?... (in a pleasing way, of course, but what does that mean? how? eg, by being particularly erudite, or adept with turns of phrase? by making observations about/describing things in a way that others haven't/generally don't..? I think those too may be part of the soul of wit...which is a plus factor almost too obvious to need stating)
...about interesting topics (but then how are charismatic people generally deemed charismatic by people with such varying subjective views on what constitutes an interesting topic? I'm going to dismiss this factor).
...I seem to be assuming talkativeness is also a plus factor. Hm
...the ability to put people at ease? to make them feel accepted? to make them feel liked &/or themselves interesting? - everyone likes to be liked and found fascinating.

These all seem helpful but no given one seems strictly necessary and even the entirety seems potentially not sufficient. Maybe I leave the mystery and magic alone.