So whats the point of a Forum then?

Just a weird thought passing my few cells, just what is the true point of a forum?
Ok, we all discuss issues etc but, for what?
I'm not talking of the Simviation forums, more forums / message boards in general.
Who are we actually talking to? Do forums ever generate something of a reaction outside the circle of forum members?
I suppose I'm asking, why do we post then? My girlfriend asked me this the other day, and its had me thinking ever since.
Surely, I could be doing something else?
:o ;D
Thoughts appreciated. :)
Ok, we all discuss issues etc but, for what?
I'm not talking of the Simviation forums, more forums / message boards in general.
Who are we actually talking to? Do forums ever generate something of a reaction outside the circle of forum members?
I suppose I'm asking, why do we post then? My girlfriend asked me this the other day, and its had me thinking ever since.
Surely, I could be doing something else?

Thoughts appreciated. :)