#Mastodon seems to implement the @DavidLibeau@twitter.com as a Twitter link. It's a bad idea.
In terms of UX Mastodon mention opens the profile collumn. Then you are not supposed to leave Mastodon.
Furthermore, people may not want to go to Twitter.com at all. In terms of privacy, I could want to escape and do not use Twitter at all.
While designing twitter.activitypub.actor, I didn't implement an easy autoredirection because of that. Users need to confirm that they really want to use a GAFAM service.
In twitter.activitypub.actor, all the data (images, username, bio) are scapped from the server side because I wanted to respect the users' right to privacy, even if it cost much more on my side.
In my opinion, if Mastodon coders want to implement mention as link, they might use a confirm dialog box when clicked and show a difference between mention of actor and mention as link in the statuses.
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