Ratings are the scale by which companies determine which shoppers to give work to and which to avoid. An 8 is a good score, 9 is better and 10 is best with the SASSIE companies (of which Intellishop is one). From time to time you will see a shop that has as a requirement that you must have a score of '8 or better' to apply. Plums tend to go to 10s and 9s.
Whether you can see it or not, every company has some sort of rating scale for their shoppers and every time you report a shop, the score for that work goes into your overall rating. You will find a whole lot of folks get nutsy when they lose a point and there is no explanation why.
The SASSIE shops start shoppers off with a 5 automatically. If you agree to do shops for them and fail to perform, I suppose your rating could go below 5.