Glassdoor was acquired by Indeed which was acquired by Japan's Recruit Co. Ltd. So keep that in mind.
Once we started hearing Glassdoor mentioned by candidates during interviews, we created a Company Page then shared it with current employees. Yes, we got a few positive reviews, then immediately staff started receiving daily recruiting emails along the lines of, "You could make $10,000 more at the same job in your city. Apply here."
As the employer on the account, we of course were not getting these emails. It's not that I have an issue with employees getting solicitations - it's the natural process - it's just a bit deceptive to employers who think creating a company page is all positive, then immediately their staff gets recruited harder.