he said this is grael, sal. you're probably having trouble scaling up your tutor yals. make lessons has videos and put it on youtube. i told them youtube is for dogs on skateboards and cats playing piano and not for serious mathematics. i got over the idea and gave it a shot. long story short from the first few videos in november of 2006, it became clear people who were not my kuz sglins were watching. by 2008-09 i set it up as a not for profit. at that point about 100,000 people were using the site. my wife and i sat down and had savings enough to try this for a year, and kind of took the plunge. i quit my job and said, look, hopefully someone realizes the social return here, the not for profit, is fairly large. it wasn't until about 2010 that we got the first real support from the gates foundation, from ann and john dor er and google. we're at 10 million users per month and we're pushing 55, 56 people in our organization. >> this is about so much more than you. you have a fairly large organization and developing sophisticated research-based tools to personalized lirni