I don't know if a circledot actually does build the self-esteem of the comment-maker, but there's some sadness in the hubskiverse and we do what we can.
I assume this is so, because every time someone post, "I'm having a bad day :(" it usually gets voted to infinity in six or eight minutes. I suppose it's a way of showing empathy in the mildest possible way. Not that there's anything wrong with that. Although I don't normally pile on, I find it kind of endearing. I'm a closet softie.