It's your reputation score - it has only been added in the last week or so.
Look at the reputation tag as there are hundreds of posts about it in there. Essentially, it is a scale from -10 to +10 or thereabouts and if you get voted up by people with a positive reputation your reputation will increase, but down votes will reduce your reputation. As with the financial side of things, I think different people's reputations carry different levels of effect if they up vote or down vote you. Look at other sites like steem.cool to check out anyone's exact rating with more detail.