I'm also interested in this question. Here's a half-idea for discussion purposes:

Review sites must be free for readers and reviewers. So, the revenue either has to somehow come from

1. end-users indirectly (like how HackerNews helps YCombinator attract quality investments)

2. a group that has users' best interests at heart, as well as a financial incentive (google's personalization helps readers find relevant searches as well as helping advertisers target... maybe not a 100% perfect example but you get the idea)

3. a diverse array of paying customers such that no one interest overpowers the others.

Any ideas in Glassdoor's context?

Why must reviews be free?

Tech magazines used to do reviews (of gadgets), and they ain't free to read? at least, not the trustworthy ones.

Are you talking about print publications?

As far as I know Consumer Reports is the only one that does this still. Consumer Reports is a nonprofit, and they're run like a media company. Their staff research and write the content, pretty well!

I don't think this would work for user-generated content -- who would pay to be able to write an anonymous review?

I do think user-generated content is necessary for job reviews; you can't buy the experience of being an employee off the shelf and subject it to objective tests, like with technology products.

It doesn't have to be paid to write - but you have to pay to view the reviews just like you'd have to pay to read a magazine.

How would the authors know they could write a review if they can't view the site?

Isn't that trivially solvable by telling them on the landing page?!

Consumer Reports.

As I mentioned in my comment below, how could this possibly work for job reviews?

Consumer reports writes reviews by ordering products off the shelf and testing them with their own staff.

How could that work for reviewing the lived experience of other companies' staff?

User-generated content is the opposite of Consumer Reports.