[zedeus]

It doesn't take much to run Nitter really, the nitter.net instance is currently sitting at 310 MB of memory and the CPU requirements aren't too bad. It's running off my dedicated home server with fairly low specs (i3-8100) tunnelled through a cheap VPS to bypass firewall restrictions. It hasn't crashed or (to my knowledge) experienced severe slowdowns despite the huge traffic increase today. Invidious's story is a bit different as the main instance load balances between 10 VPS instances.

Regarding usage stats I don't have any accurate numbers, but the database that stores preferences has 30k rows.