Listen to John Follis discuss G-cred:
Web visibility is credibility. That’s the essence of G-cred™ A G-cred Score is a general measure of that. The “score” will appear as a number under the search bar after doing a Google search. Just understand that your G-cred accuracy is contingent on using proper Google search technique.
As a general measure of online credibility a G-cred Score is something that can (and probably should) be checked on a regular basis. Doing that will let you know if your G-cred is improving, or not.