One of the fundamental differences between social media and email is that social media is a pull—you actually have to go looking for content to do something with it—whereas email is a push. I send email to you, whereas with social media, I've gone someplace to see something.
Where the line gets is blurred is something like LinkedIn, where you've gone on the platform to maintain your professional relationships with someone else, and then someone starts sending you advertisements for something. That sounds an awful lot like push, whereas in general, little companies have their Facebook pages, their friends, their colleagues, and they write comments about the food they have and all that sort of stuff. That's very much a pull. That's not being slammed in my face. It's not requiring me to spend money that I wouldn't normally have spent to deal with it. It's purely voluntary. I have opted in by using my eyeballs on it. I've actually gone looking for it, whereas sending unrelated advertising to a LinkedIn account is a different thing. In fact, especially in the example of LinkedIn, the only thing that's really appropriate for LinkedIn is advertising for job offers.