I saw on one of the intro threads that the button on the left is not an upvote—it shares that post with whoever is following you. Does it work that way for comments, or is that more like an upvote, where it doesn't share with anyone, just moves it up in the thread?
With comments its more like what you are used to with an up vote. It raises it in the comment threads. Good question though and welcome to Hubski. Check out the Primer Page for more info.
Edit: Also, I like your username. I'm taking violin lessons with my 4 year old daughter. Had one today.