Forget Snapchat. One of the most speculated about potential IPOs in Silicon Valley this year is file sharing and storage company Dropbox.

Dropbox was one of the earliest Valley unicorns to seem to defy any logic in valuations, and at its last round was valued at $10 billion making it one of a handful of so-called “deca-corns.” At one time, it and Airbnb made up some 95% of the value of Y-Combinator’s entire portfolio. And it was backed early on by top venture capital firms Sequoia Capital, on their way to raising some $600 million in capital. Its office was so lavish it reportedly spent up to $40 million a year just on employee perks. Its lobby sported a $100,000 statue of a Panda.

Yes, for a while, Dropbox and its co-founder and CEO Drew H...