Hi guys there is plenty social media platforms which are the best to promote ICO my favourite are
1 Facebook
2 Twitter
3 bitcointalk
4 Reddit
Best Bitcointalk and Steemit. Facebook and Twitter not much effective. But you can find community members from them. But for the investors, the best place is the Bitcointalk. Reddit and Linkedin are also good. many ongoing ICOs give more stakes and rewards for the Reddit and Linkedin campaigns. so from above 4,
1. Bitcointalk
2. Reddit / Linkedin
3. twitter
4. Facebook