Erik Dungan, a web startup veteran, built Anonysize.me, an app that anonymously finds the correct size of a gift recipient's shoes using Twilio SMS, Ruby on Rails, and other technologies. The app was created in just two days during the Zappos Holiday Hack-a-Thon and quickly gained popularity after being posted on Hacker News. Anonysize.me connects the sender with a Zappos page of shoe suggestions when the recipient responds, making it a perfect solution for figuring out the right size without giving away the gift. The app uses various technologies to provide a seamless experience, including Twitter Bootstrap, Google Web Fonts, Pusher, and SendGrid.