Just for documentation, this feature request was implemented a couple of months ago – see 2.8.0.beta9: Tag Descriptions, Recent Searches, Sticky Avatars, and more
@here support
Users can now mention @here to notify 10 people who replied to the topic. Admins can manage permission to use the @here mention, and the number of users mentioned, via the
max_here_mentionedandmin_trust_level_for_here_mentionsite settings.