Now, if we wanted to get systematized about this, what we should do is only give rep to someone with as many dots as you or fewer. If you have 1 dot, stick to people who's rep says NOOB or Zero points or something. Otherwise you'll just be handing out greys. So even though MichealX and STLee and others have helped me out with greens, I can't do much for them until I get my Rep up to their level (wish it were otherwise, but....)
Looks like it's a trickle down model (you can get increases from people higher up the food chain than you, but not from equal or lower). Sort of a Supply Side Rep-onomics....