It's hard to get help from friends on tough homework problems or academic concepts in general over tools like Facebook Messenger or Skype, which weren't really built for educational purposes. I love how you can instantly create a comprehensive virtual class with a fully collaborative whiteboard, built-in Twilio voice conferencing, and text chat and share the link with my friends and learn/teach effectively online in real-time for free (with no ads). It's also built in HTML5, which makes it able to use with iPads.