As you may know, on leefish we have the "Mention Me" functionality. You put an @ in front of a username in your post and the "mentioned" person gets an alert.
This has been a bit fiddly as it required you to spell the name correctly. We now have an update to the function where you will see a "megaphone" icon in the postbuttons. Click that and it will add the users name to the quick reply box - you can select multiple users too.