The Opinions Credit = Opinions Given - Opinions Received. Negative means that you have received more opinions than you have given.
What this means?
When we all post blogs we want to receive replies, opinions, etc. This is the "reward" or acknowledgement of our participation. However, sometimes, we ourselves don't care much to provide opinions to other people's posts. A positive opinions credit means that you are fulfilling your social obligations by giving opinions to other people's posts. Others will see this and may be more willing to reciprocate. To turn your opinions...
more... credit positive, just provide some opinion to other people's posts. For example, many people provide very useful answers but they don't receive any Thanks or may receive just 1 or 2 opinions. So, just add a "Thanks" to such a post to show your appreciation.
Very soon the "Opinions Credit" will also start appearing next to a person's name in the blog so that others may readily see how willing the person is to provide opinions himself.
Thanks.