1. Samsung doesn't write that app so be sure to ask Facebook to add it.

2. Smart Hub's intent seems focused on consumption. This was noted at http://televisions.reviewed.com/features/samsung-s-2013-smart-platform-explained
"If you learn anything from this guide, it should be that Samsung put the Smart Hub's focus on accessing content, not meaningless apps."

In short, this is not going to replace your PC, smart phone anytime soon.
Bob