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.

This. One cannot post anything on Glassdoor today without first establishing an account. Nearly all companies that create accounts use services to “enrich” your user data via the IP, email address, etc. so they grab and keep that data. It is certainly no longer anonymous if it ever was.

> I had to provide a company email address

You mean you had to currently be working there, rather than formerly? I thought this lawsuit was about people who had already left Zuru, but I may have misread the article.