I'm not sure this would be possible via normal subreddit admin tools but I'd like to see this done as an user opt-in feature. Let people post those link if they

I'm not sure this would be possible via normal subreddit admin tools but I'd like to see this done as an user opt-in feature. Let people post those link if they choose to but also let users choose if they see them or if they get a notice when they try to post a link to one.