I can only provide examples, but let's speculate.
Let's say your current main connection to the tree is through (had to look it up) the Culver family. So this leads to other families, and eventually to the person on the Global Tree.
So let's then say that you fill out additional smaller branches and leaves, and end up finding that one of your relatives married a Miller, whose sister married a Bacon, who just happened to be Kevin Bacon's great-grandfather. Once that connection was created, and the links updated (happens nightly), you would check again and a new connection would show up in the connection finder and for those who it provides a shorter path, you would see the numbers decreased as to how many steps away they are.
Was this what you were looking for? Basically any additional connections you make to the tree will allow the finder to use all of them to find the shortest path between the two profiles.