Jeremy Foster and I had no idea what kind of response resulted from presenting our free training course to prepare for the 70-480 exam. For example, who knew that our shirts (purchased from the Microsoft Store the day prior) would become so popular, people contacting both of us wondering where they could buy one?
That said, the real story is in the successful outcomes of those who watched the videos and then subsequently passed the exam. Even more impressive to me personally is that some already have apps submitted to the Windows Store! (Do you have an app in the store? If not, consider 30,000 reasons why you should submit your app now!)