> Isn't it possible to rig Glassdoor by using multiple accounts?

Yes, they don't check your identity.

And HR departments have paid to improve companies public perception... It's easy to guess they'll spend time rigging Glassdoor.

I've seen and heard plenty of horror stories from companies with good Glassdoor scores.

I wonder how many people lie to themselves when evaluating their jobs.

From what I know, it's not that "people lie to themselves" about those terrible jobs, but more like the article describes: concerted effort by the employer to flood their reviews pool with inaccurate positive reviews, and muzzle accurate negative ones.

Glassdoor seems to be very biased toward low salaries globally - unsurprisingly.

That only benefits employers in general.