I think this talk about tracing traffic could well be missing a bigger point. The last time I left a Glassdoor review I had to provide a company email address to do it. This means, although publicly my review was anonymous, Glassdoor knew (and very likely still know[0]) exactly who left it. If they have to hand over email addresses to the company taking legal action there's no need to get clever with traffic tracing.

[0] Even with GDPR and similar legislation all they need is a valid business reason and they can keep my PII.