One of the things that sets Jimmy Fallon apart from his late-night competitors is his show's embrace of social media. Not only does Late Night with Jimmy Fallon feature a regularly occurring bit called "Hashtags," the future Tonight Show host sat down with frequent guest Justin Timberlake for a skit that takes Twitter-speak to an entirely new level. And sure, using a hashtag as the punchline of a joke has become a familiar comedic trope, but the guys' chemistry and timing make the bit worth watching, and seeing the two rap together always makes for good television. But it's the Roots' Questlove who steals the show. Check out the clip below.