Each time someone gives you reputation points the bar progresses ...
This feature extends the existing reputation display system from just the light/dark green pips to green and golden pips, and then a series of bronze, silver and gold stars as the pips limit is reached.
The dark green pips are followed by light green pips, which are then followed by gold pips. When the limit these can display is reached, the (prefix) display of stars begins - starting with the bronze stars, then silver stars and finally gold Stars. If your reputation is zero then the neutral grey pip is displayed. Negative reputations are displayed in a similar manner using light and dark red pips and red stars - however, there is only one star level for negative reputation.
Each time you 'lap' the limit of the pips display, another star is added.
So start giving each other reputation points !!!