(enhancement)

When selecting "challenge complete" the pop-up gives you an option to tweet about it:

I just ROCKED Free Code Camp Challenge #4: Build a Responsive Blog Theme http://freecodecamp.com/challenges/4 #learntocode #javascript

Perhaps consider changing the text to include the Free Code Camp username. The same message is conveyed, but gives an additional lead opportunity to the Twitter account:

I just ROCKED @freeCodeCamp Challenge #4: Build a Responsive Blog Theme http://freecodecamp.com/challenges/4 #learntocode #javascript