FIX: Where is a user notified that one of their actions has been throttled for the day?

Meta: [Where is a user notified that one of their actions has been throttled for the day?](http://meta.discourse.org/t/where-is-a-user-notified-that-one-of-their-actions-has-been-throttled-for-the-day/6027)

This will display a nag whenever a user is getting its his actions throttled:

![image](https://f.cloud.github.com/assets/362783/404489/fe7e93e4-a94a-11e2-9271-6122fc0469b5.png)