I had no idea how Hank Green was going to follow up the first book in this set, which I thought was a stand alone at the time. I was very impressed at how he was able to develop a new level of complexity with the alien threat, yet never lose track of what made the first book interesting: that it was a story about a group of friends trying to figure out how to use their huge social impact for good. Green is very knowledgeable about things such as becoming famous for a niche thing and growing a huge social media following. These are major threads of the story, but so are the relations of human brains to computers, the future of the internet, and the ways in which communications technology can unite or divide us. A satisfying sequel.