Among Houston's annotations: A screenshot of his bank account, showing the moment when he reaped the benefits of Dropbox's first-ever funding round—$1.2 million from Sequoia Capital.
"For a 24-year-old, this is Christmas—and opening your present is hitting refresh over and over on bankofamerica.com and watching your company's checking account go from 60 dollars to 1.2 million dollars. At first, I was ecstatic—that number has two commas in it! I took a screenshot—but then I was sick to my stomach. Someday these guys are going to want this back. What the hell have I gotten myself into?"
Among Houston's first purchases is a $17.35 splurge at Radio Shack.