Our classes apparently are different. We didn't have TIME to talk. Lecture started at 1:00 PM. Lecture is supposed to be out at 1:50. Lecture runs over until 1:57 because that's how chemists roll. Next prof is waiting outside tapping his or her foot impatiently. No time for tea and crumpets when there's science afoot!
We also had course administrators, so there could be six sections of general chemistry lecture that all did the same assignments, and therefore could work together and study together. FB brought us all into the same loop, and it let us all communicate with each other.
Nowadays, our university uses Blackboard to give us the same option to email classmates, so it's not like it was just a trend for introverts.