Perhaps it's just me, but from time to time I see people confusing following a bunch of people on Twitter with having developed an online personal learning network (PLN). There are two flaws with that logic. First, to get the most (however, you define that) out of your PLN experience you have to interact with people. It's hard to interact with all members of a large group which is why I've made many Twitter lists (some public and some private). Through lists I can keep up with and interact with the people that are really my PLN. Second, PLNs can exist wherever you want them too. The video below from John T. Spencer illustrates that point quite well.