To expand on
https://danluu.com/sounds-easy/, 10k people aren't required per se, they're there to make more money than they cost. Specifically:
- sales & billing for linkedin premium, lynda, and other paid products
- billing fraud detection, to cut the cost of chargebacks
- security, to prevent that one leak from happening again, to keep PCI compliance, etc.
- spam filtering, tuned to balance keeping paying customers (recruiters) happy with keeping suppliers (candidates with a resume) happy
- Writing new features, to keep engagement and signups up
- fixing things that keep breaking, like the email contact scraper
- testing code for new features to make sure they, IDK, don't break the signup page
- a/b testing the hell out of any and every thing
- collecting and storing the massive analytics datasets they generate daily
- analyzing daily datasets to determine which a/bs to promote
- coming up with new features
- testing anything at all
- deploying corporate networking in all the offices buildings and such
- optimizing infra costs
- deploying actual physical datacenters because the cost is cheaper than paying the profit margins of AWS
- moving back to cloud (azure) because after you were acquired, the markup dropped and the calculus on on-prem vs cloud flipped
- managing all the projects associated with above
- recruiting staff to handle all the above
- managing all the staff associated with above
- acquistions (lynda, fliptop, glint, drawbridge)