Lena was a freelance graphic designer, which meant her “office” was a noisy coffee shop, and her “filing cabinet” was a tangled mess of USB sticks. For three years, she had a system: work on her laptop, save to a tiny blue USB drive, then plug that drive into her desktop at home to back things up.

Not under the car seat. Not in the bottom of her tote bag. Not in the pocket of yesterday’s jeans. It was simply gone . And on that drive were the final mockups for a client presentation due in six hours.

But here’s the magic she hadn’t expected. Marco said, “Now go home. Open your desktop.”

That’s when her friend Marco, a software developer, messaged back: “Stop emailing yourself. Just download the Dropbox desktop app.”