Back in September. I wrote a post urging educators to join the Q&A site Quora. Looking back at that post now, it's sort of funny. In it, I make a case for teachers joining a site that at the time, few people in education circles had heard of, suggesting they do so in order to add their voices to a site that was dominated by bleeding edge tech, Silicon Valley folks.

Since I wrote that post, Quora has exploded in popularity, something credited in part to the famous Scoble effect when tech evangelist Robert Scoble joined the site over the holidays.

But what strikes me as funny about this three-month old post isn't that everyone's now on Quora. Despite what's been a massive growth spurt for Quora, it's still a rather closed circle. In some ways, I think, people would argue that's a good thing as it's what's keeping the quality of the Q&A high. But on the other hand, it means that both the questions and the answers really only represent a small piece of inquiry and expertise.

I've been watching the education-related questions with some interest, and I would love to hear from educators who are using the site. (How long have you been a member of Quora? How are you using it? Are you finding it useful?)

As you can see with the spat below between investor Keith Rabois and professor Vivek Wadhwa, it's a contentious issue -- one that I've decided to Storify not just because it's a decent Twitter fight but because in those 2 figures you have a voice of the Valley (Rabois) and a voice of education (Wadhwa).