isn't PoW supposed to be feature to prevent spam, why aren't we using that more?

Anything can be tried, and there is no reason not to try this. But I still think it's a bad idea. Suppose it became a very popular relay, what would prevent a few popular and influential accounts from colluding to ensure someone they don't like can't post to that relay? I suppose it would depend on the policies that govern the censorship. My concern is that it creates a "mob rule" situation where others could be unfairly silenced.

@corndalorian be baseless fear mongering