How many? Why? Are they different from one another? Are the folks who belong very different from each other and one another? Does each have its strength and its weaknesses? I gather that having a lot of followers indicates popularity and I expect folks with bazillions of followers have/take bragging rights, right?
Then there are the bloggers and what is a pod cast? What does the POD mean?
Used to be we wrote letters and it took forever for the Pony Express to get the mail through. There was the telegraph of course but that wasn't bigly popular. Then the phone came along and that was a real timesaver. Then the internet and email which is a joyful thing to me. But what else is out there that facilitates communication among homo saps who are so inclined? Do you belong to just this one, some, many or ALL of them because you don't want to miss out on anything? How do you have time for all of it?