And also, more importantly, the dots tell you how many times a submission of yours has been shared. If I post something and only my (few) followers see it, but then thenewgreen "upvotes" or shares it, all of his followers will see it on their feed. So if you post something good, it's built into the system that more people will see it -- like reddit. But unlike reddit it's not based on the quantity of people who share your post, it's based on these sharers' quality, as it were. (How many people think they share things worth reading.)
So the value of your shares is based upon the amount which the sharer has, in turn, been shared? That sounds a lot like PageRank, Google's ranking algorithm, which ranks pges based upon the number of relevant inbound links from pages which in turn have a high PageRank. (tip: to understand recursion, one must first understand recursion)
That's an awesome bit of information to know about, and paints a better picture of how hubski works. Thank you for sharing that!