What does that mean? The "algorithm" could be anything, possibly not even an algorithm.
It's so silly, it's sad.
The fact venturebeat only shows Tech company makes it a bit better than the original ranking since it's at least comparing Apples to Apples: On the original ranking the fast food chain In-N-Out, or grocery store HEB is a better place to work at than Apple, or Microsoft (not even in the top 50 in that list)
But even, a startup and a tech giant shouldn't be on the same list.
The ranking can be found here: https://www.glassdoor.com/Best-Places-to-Work-LST_KQ0,19.htm
EDIT: Also presenting best companies to work on 1 dimension is somewhat useless. Glassdoor probably weighted Salary, Flexibility of hours, career opportunities, etc. their own way. A better ranking would let you weight the different options yourself, or at least give you the option of a few presets weights: Best place for 'workaholics', best place for family people, best place for career growth, etc.
Unless you think they're lying?
E.g., Uber is a 4.4 on glassdoor right now, where are they?