also, discovery happens in replies usually anyway, someone says something you like, you follow them, then you see their OPs

there probably needs to be some mechanism for association to the status as new user so they can be given a little visibility for this

> free trials and rate limited freemium service

That's probably one way to do it. Still, could easily be gamed by bots by deploying new keypairs and IPs. I'm not sure there is one-size-fits-all for relays here. Either you accept some spam with rate limiting/PoW/freemium services or you deploy a paid relay with whitelisted pubkeys and/or heavy moderation.