Why are there so many social media and so many websites you have to have an account for?

I mean we have twitter face book tumbler pintrest, but there's these other websites like in order to post something you have to make another account for it. There are so many social media out there. And along time ago we just had my space and could read from books instead on those flat computer things and why is every one getting the same iPhone and i pad.what's up with all those twitter stuff like hash tag, selfies, photo bomb, instagram, Doppler or scan your phone. What happened to talking on the phone rather than text or writing a letter to someone rather than on face book or text. If you agree with it or not.comment.

Because those you don't need an account for tend to get flooded with spam and other abuse