I noticed at 9gag.com/fast that if you click the Like
button, a small option opens up to share that link on the user's wall.
I believe this is not a default option because I have implemented the Like button on my site and it doesn't work that way.
How to get this functionality...
Use FB.Event.subscribe('edge.create')
as described here with the JS SDK to catch the event when a user likes your page.