The scope of the question is really big and can't be answered completely with the scope of this thread. However, I have been using few social media platforms since a long time now and I found Facebook, Twitter and specially Linkedin are more influential on cryptos! Facebook and twitter are used for general marketing of cryptos while Linkedin is used by the business owners in crypto space to get more visibility and business orders!

For content creators, I see Medium is especially good but Medium has some kind of strict policy towards cryptcurrencies and a lot of people have got their account banned in Medium for violating such policies! For content also, I found Linkedin is good enough to showcase your skills! hope this helps!