I think there's a bug in the StackExchange achievement system. I received an announcer badge for a question that I've never seen before. What makes it even more look like a bug is the fact that my user id is 606, and that the user who asked that question is 6066.
It might just be that the achievement was awarded correctly, it was the asker who did it wrong.
The way this badge works is as follows. When I click on Share on this post, I get this URL:
That's because I'm user 23. If you press it, you'll get:
Whenever one of these URLs gets clicked on enough, the badge is awarded to the user ID embedded in the URL.
If user 6066 didn't share the URL in full and left the final digit off... it's not a bug, it's an user error. :)