hubscore is a quality metric used by HubPages. It is controversial to many here, because no one really knows "exactly" how the algorithm calculates the scores. The higher a hub score, the higher the quality of the hub - allegedly. The Hubber score (the number on your pic) is another number that no one can really tell you how it works. It goes up and down and is based on a number of factors in an algorithm. Not something you can really control, except for creating high quality hubs and doing your best. I recommend you view and read the content of the learning center before digging in. There is a lot to learn and the more you know; the better you will do here in the long term.