Keepin' it simple.
Out of the box Craft doesn't offer a way to moderate new user registration gracefully. Concierge does just that.
When a new user registers on your site, Concierge will:
- Suspend the new account
- Send a holding email to the new user
- Send a notification to a moderator
Once a moderator activates the new user, concierge will send a welcome email notifying the user her account is active. Et voila.