We've all heard about successful startups like Uber and Snapchat, but what about the ones we haven't heard much about? Here are the top 5 startup companies worth a billion dollars that you probably have never heard of. Starting the list at number 5, Good Technology. The Sunnyvale, California-based company provides a secure mobility platform for enterprises and governments worldwide. Its equity funding is almost $400 million. At number 4, Evernote. This company is a note-taking app that can live across technology platforms, including smartphone, tablet and computer. It has just over $300 million in equity. Coming in at number 3, CloudFlare. The San Francisco-based company is a web performance and security company with more than $70 million in equity. Number 2 on the list is Yello Mobile. This is a mobile business platform comprised of 54 companies. According to its Web site, it 'invests in the fast growing sectors of mobile and digital.' And number 1 on the list, Home24. The Berlin, Germany based furnishing and design Web site has $20 million in equity.