It doesn’t 
I can link a forum post like this NEW FORUM GUIDE - SYNTAX AND FEATURES and it works fine. If you go to that forum sticky. Level One trust level can post links to " * Create links and video embeds to trusted websites like Blizzard websites, YouTube, or Twitch" if I try to post a link like ~www.death-jesters.net~ based on the same post I need to be Trust level 3 to " * Post animated gifs, images, compatible video embeds, and links to any website" and I get “Sorry, you can’t include links in your posts.”