The global inbox contains information from across the entire network about notifications regarding posts and comments you've made, from answers to your questions to @replies to your comments.
The global inbox contains notifications directed at you from the entire network, from answers to your own questions to @replies to your comments. You can access the global inbox by clicking on the box icon in the top right corner:
Use this tag for any questions related to the drop-down global inbox and its functionality. If you have questions specifically about notifications inside the global inbox, you may want to include the notifications tag with your question.
For questions about the achievement dropdown located just to the right of the global inbox, use the tag achievements-dialog.