I actually use Twitter a lot, to advertise my novel. I love Twitter, although less so, now that my novel is published. But I can tell you that it is a great place for networking, more than Linkedin because you must use photos on LinkedIn (which I think hurts more than helps Black people--I make my living on the Internet as an attorney, and my clients have no clue of my race until the discussion of race comes up -- AFTER I've proven what I can do for them).
I think Twitter's usefulness depends upon what you use it for. I like to talk politics, and it's opened my eyes to a lot of diverse views. I have a lot of conservative followers with whom I discuss Black issues, because the dialogue is important and they don't always talk with Black people candidly. I found @aalbc on Twitter! I have made a lot of contacts. I've had people with whom I've dialogued purchase my novel.
I think Black people have a larger voice because of Twitter. #BLM, Shaun King, and even Joy Reid, Deray got their fame and/or jobs because of Twitter, to my knowledge for better or for worse. I could go on and on. So, I'm a Twitter fan, but less so, now that I need to market my novel in brick and mortar stores. Personal contacts ALWAYS work, but access to people is the problem. Facebook advertising is 100% better than Twitter - $50 goes a long way (I'll be using @aalbc during the holidays).
Let me just add that the reason Twitter works is that corporations get to hear from their customers. I have tweeted corporations to complain, to extol good customer service, etc., and get a 99% reply. I've been mentioned 3 times on C-span. I would not get a voice otherwise, in my opinion. Corporate America cares about demographics. They get it on Twitter.
I agree that the shaming on Twitter is deplorable, and the fact that it is anonymous is problematic. And I hope that is changed (I read that Twitter is going to stop the trolling).
Just my thoughts.