You can assign a 1 to 5 rating to your profiles, by clicking the stars above their names in the People galley, work session or album. You can also add the rating from the profile window, located on the right side below the picture.

To remove the rating from a profile, click on the stars and then the little ‘X’ icon that will appear at the left of the first star. To change a rating, just click on the star you want to change the rating to.