Is there some principle that if everyone has heard of a company and you don't feel you have to explain who they are then they are probably a minimum of X thousand people?
And so they outsourced everything to others. Their 2013 expense is $148M for $10M of revenue[1]. They aren't spending $148M on 55 employees for sure. And that doesn't include server cost(which is likely very low due to optimizations).
[1]: https://www.sec.gov/Archives/edgar/data/1326801/000132680114...
And most companies making billions need thousands of employees, especially software devs need to understand that.