1. Gmail is used for sign up and login authorization because the majority of targeted teams use it.
2. The sign up flow is designed to make it easy for only one person to invite their coworkers, helping to accelerate growth.
3. The app contains three different types of games to keep Flock fun, yet not too many that it becomes overwhelming.
4. Flock's UI is minimalistic, allowing users to focus on the two elements that matter - the question and the timer.
5. Angular's drag and drop is used to make the game more interactive.
6. When a guess is made, a green or red indicator glows around the images to reveal if the guess is correct or wrong.
7. A leaderboard is integrated to keep the game competitive and fun.