re: Mastodon link previews
I'd just like to interject for a moment. What you're referring to as a Mastodon DDoS, is in fact, Mastodon Request Amplification, or as I've recently taken to calling it, Mastodon plus Request Amplification. Request Amplification is not a DDoS unto itself, but rather another free component of a fully functioning DDoS system made useful by the REST API, Sidekiq jobs, and vital link preview generating components comprising a full Mastodon server as defined by Eugen.