Another feature update courtesy of open-source contributors - @Celeo was brave and took this complex update on as a first contribution to the Tildes code.
Mentioning a username in a comment will now send them a notification. Any of the following formats work:
It won't send a notification if you mention yourself, or if you mention someone that already would have gotten a notification for the comment anyway (the author of the parent topic/comment).
Edits should be handled as well, so if you edit in a mention that wasn't there previously it will generate the notification at that point, and if you edit one out it will delete that notification (whether the user has seen it yet or not).
Please let me know if you notice any issues or strange behavior (and please don't use this maliciously to annoy people).