But (presumably) those seven posters would be motivated by big tech money and thus be identified by some algorithm or the other in that blockchain? And/or you being a genuine reviewer would have a more organic activity across the blockchain with other products too compared to theirs and that will add to the weight?

There's just very little organic activity on a site like Glassdoor. You changing jobs, and thus naturally having any kind of inclination to post something may be few and far between, and you might not even think of uploading a review unless you're disgruntled (read: motivated).

> (presumably) those seven posters would be motivated by big tech money

Probably not, I think. They're more likely to be employees or friends/family of the company doing it because they were required or asked to.