EDMODO BOOM: It's getting bigger. Edmodo, the social network for teachers who want to share with either teachers or with students, hit 15 million subscribers this week, a 200% increase in subscribers over the course of the year. (Here's 2 minutes on Edmodo's history from its cofounders.) That includes 1.3 million teachers at more than 120,000 schools and nearly 12,500 school districts. Most interesting: the most active time for Edmodo users is Thursdays from 11:00 am to noon ET. (Hope you're reading a fresh copy of EdSurge during that sweet time!)
