Facebook - Potential and current employers, insurance companies, credit card companies, etc. can and have used people's facebook profiles already to judge them based on the material they post.
Google/Youtube - Google can add you into their search engine so anybody can type in your name and pull up arrest records, personal blogs, even forum posts on extremist websites. The videos you share can be used to target you for hate/death threats and can be used to silence you if you do not fit into Google's "preferred speech".
Twitter - people have been fired or lost job opportunities for posts made years ago.
These all seem like social credit profiling to me, but what do I know?
Right now, I, personally, can't confirm that they are giving "ratings" to individuals, but that is a possible next step.
I also said nothing about rating companies. Not sure why you brought that up.