It can be used as an anonymous reverse proxy, meaning it could be used to host malicious or illegal files on a malicious users computer, while making it more difficult to trace back to them. Any complaints will have the service IP address rather than the malicious users, meaning the server host is the first person the feds will be questioning during an investigation. And when I say questioning, I mean potentially publicly arresting the host for child porn or similar, destroying their life (despite being innocent), or holing the hosts computer equipment as evidence for months / years as part of the crime, even with irrefutable proof of innocence on behalf of the host.
On the things not to host, a public variant of this would be at the top of my list, right next to tor exit nodes.
On the things not to host, a public variant of this would be at the top of my list, right next to tor exit nodes.