Learning about the costs of running a Mastodon instance for even <1000 users highlights how Twitter also wasn't free, even though users thought it was. There were enormous costs, and we paid for them.
@samplereality Twitter was written in Ruby at first too, but Ruby wastes 99.9% of your CPU and 90% of your RAM, so rewrote it in Scala years ago to make the costs much less enormous.
@samplereality Well, it might be a more conservative estimate to say that Ruby wastes 99.7% of your CPU.