Hmmmm... No one really knows..lol.. Maybe a symbol of how wise or respected that others here think you are? I don't know..I don't even know how or when I gathered 152 powers. lol
When you get to 50 posts, you'll get a power. After that, you make a pre-determined number of posts to get another power. Mine is currently 1000 posts.. When people rep you, you gain as many points as they have in powers. Sometimes that will bring you up by 2 or 3 powers. For every 100 rep points you get, you receive one power. As for the green bars, you start off with a little pea pod, and end up with a cucumber..lol