This is a collection of thoughts from a maintainer of the Public Suffix List (PSL) about the importance of avoiding new Web Platform features, security, or privacy boundaries assuming the PSL is a good starting point.

Equally terrifying, however, is how many providers only discovered the existence of the PSL once LE was using it to rate limit - meaning that their users were able to influence cookies and other storage without restriction, until an incidental change (wanting to get more certs) caused the server operator to realize.

source: HN