The wall post reads:
The illusionThis link redirects you to a website – doyoulikefacebook.com. Here, you are shown a youtube video which is actually not a video. It hides the like button. When you double click it, you like the page unknowingly and you are taken to the page.
The illusion or not ?
Is there a bug in Facebook Like button?
This app utilizes a bug in Facebook like button. You are made to like a link without clicking on the like button. Though it app does no harm, this technique can be used in liking pages that contain virus or Malware.
So, ignore this wall post and be safe on Facebook.