Our employee evaluations are:
1 = "does not meet expectations"
2 = "partially meets expectations"
3 = "fully meets expectations"
4 = "exceeds expectations"
5 = "outstanding"
Everyone's scores are "calibrated" to a bell curve. 0-5% of employees get a '1', about 5% get a '2', 65-70% get a '3', 15-20% get a '4', and 0-5% get a '5'. I know of no one—including myself—who's ever had a '5'.
3 or better means we're definitely keeping you around, and 4 or better generally means a candidate for promotion. '2' is basically "we still want to keep you around but there are things you
really need to work on", and '1' is "shape up or ship out".
I definitely think of online reviews by the same metric, or similar anyway. 3/5 is perfectly cromulent, 4/5 is exceeding my expectations, 5/5 is wildly exceeding my expectations. Like others have said, I barely pay any attention to reviews, and when I do I tend to discount the 1s and 5s entirely anyway.