I "used"(found excuses not to use) this at a previous job at a mid size software company.
It was literally just a private instance of facebook. 95% of the posts were basically fluff posts from HR. No content of any substance. So basically linkedin, but less useful, because everyone on there was in the same company and so there was no real networking effect to it either.
I didn't stay at that company very long, for a multitude of reasons.
Then it's will turn into the one true cringe generator.