The brother to John Green, Hank Green is the founder of the environmentalist technology blog EcoGeek. He is most well known as the "younger half" of the Brotherhood 2.0 project of 2007. Inspired by Ze Frank, the Greens gave up textual communication with each other for an entire year. Instead, they spoke primarily through YouTube vlogs, under the username vlogbrothers.
Eventually, during the run of the show, Hank wrote two songs each month. The show became widely known after Hank Green posted a song about the last Harry Potter book, "Accio Deathly Hallows." A huge fanbase grew up around the show, and its devotees became known as Nerdfighters. Hank, having created DFTBA Records (that stands for Don't Forget To Be Awesome), can now be said to be a professional musician.
The vlogbrothers continue to make regular videos, often featuring Hank's songs.