Have you ever gotten stuck while using an online resource? If so, which one(s) come to mind?
Examples: Codecademy, Code School, Treehouse, One Month (Rails), Learn Python the Hard Way, Udacity, Coursera, Harvard EDX, O'Reilly book, Nodeschool.io, Official Documentation That Was Hard To Understand, Popular Technical Blog Post That Didn't Make Sense In Some Parts, etc.