Try doing the same with other members and compare the messages appearing when there's 1, 2, 3, etc... green blocks.
o --> X is on a distinguished road
oo --> X will become famous soon enough
ooo --> X has an spectacular aura about
...and so on.
I guess the number of green blocks is kind of a "reputation" level indicator.
Again, I guess you get green blocks with time+posts+thanks from other members.
I'm just guessing anyway.