I'm in a group and I posted something. Then, beneath my post it says "seen by 2" and when I click it, two users names are displayed.
Facebook Group – What Does ‘Seen by 3’ Mean on a Post?
Related Topic
- Facebook Seen Message – What Does ‘Seen’ in Facebook Message Dialog Mean?
- Facebook – What are post clicks on Facebook
- Facebook: When I upload new images to an album, how to change what photos are displayed in the wall post
- Facebook Admin – How to Post or Comment in Your Group
- Facebook – Why don’t shares of photos from the page to a group show when the group post is re-shared
- Facebook – Difference Between Share and ‘Who Should See This’
Best Answer
It shows you how many people have seen/read it and (via the link) who they are.
It's a recent change (as of 28th August 2012) that's just been announced.
Here's a Techcrunch article that explains it in more detail.