This is more limited than the post implies. It only applies to some parts of Discoverable Servers. Private Servers, Community Servers, DMs, group DMs, and private or role-restricted channels in Discoverable Servers are excluded too. Usernames and avatars are not shown next to messages. We made this update because over the years people told us useful info that used to be findable on the web had gotten hard to track down. Admins and members get to decide how their content is shared, or can opt out completely. Starting today, admins can pick which channels take part, or opt out entirely, in Server Settings > Web Presence. If you don’t want your messages shown, turn it off anytime in User Settings > Data & Privacy.