As a marketer who helped manage various companies' reputation online, I can tell you that Glassdoor is pay-to-play. If you pay them the subscription fee, and you get negative reviews, whether "true" or not, you can challenge most and get them removed. I thought most people would understand their business model explicitly relies on getting companies to pay a fee to own their page (and in turn they have to keep those customers happy by removing reviews they don't like) but I continue seeing recruits relying on this site as if it's some unbiased source of info.