I'm not exactly sure how to get it back.

• You might try closing all your browser windows and restarting your browser. Go to SteemWorld and see if it gives you the option for notifications.
  • If that doesn't work, I'm guessing clearing your cookies should do it...
    • Maybe @steemchiller has a more definitive answer?
• Good luck. Let us know what works for you...

Yes, I occasionally have other people's SteemWorld pages up and get notices from them...