Notify issues to mentioned users by mail (BB-7130)
Currently, it's possible to assign an issue to a specific user, or team. There's no mechanism to CC someone on an issue, or request his involvement by replying to the issue discussion.
Naturally, I think that mentioning someone by his nickname in an issue (@ nick), should send him an email containing the issue he was mentioned in. In case of a private repository, the user must have access to this repository to prevent sending classified issues to unauthorized user by mistake.