Are Glassdoor Salaries Accurate?

I've been checking out the salaries in Glassdoor for the company I work at, and they seem quite low. I don't know if I'm actually overpaid, or if the salaries on Glassdoor are inaccurate, or possibly fake. I wonder what everyone's experience has been with Glassdoor. Do you find the salaries there too low, too high, or accurate for the most part?