Note that feeds created here can be followed by anyone on any server, but the people who can make new feeds are limited to your users who have already agreed to your terms of service, and who you can suspend etc if they use this RSS mirror thing poorly.

I tried running a public version of this and it was overwhelmed by spammers and also I had to keep track of like... taking down harassment-focused RSS feeds etc. Easier to just limit it to people I trust.