The word 'Ding' is a gaming word for the phrase 'I levelled up'.
'Ding' messages are usually reserved for friends, or your members of your guild- as people in the general chat show hostility to your level-up.
May appear from time to time as part of another word; eg. 'Ding Dong', 'Ding-a-ling'. etc.
Feelings of joy and happiness usually surround this word, increasing in intensity with higher levelled 'dings'.
Me 'Ding!' ... Friend '
Grats!' ...
GZ
'Gary Coleman, I'm only three bars away from a ding'
'I'm going to get my ding then
log'