As far as getting content out there to the most people, I think Facebook wins due to their sophisticated advertising platform.
Branded Content vs Content Brand
I think that tactic (of building a content brand) can work for a lot of organizations, but not all. For me, it always goes back to what is resonating for the customer. Who are your buyers and how can you position your content (branded or not) to best attract them.
Your favourite content generation/marketing tools
I use a variety of tools for my daily content from Google Alerts to Canva for visual content. I also use the social platform Hootsuite (their suggested posts feature is fabulous), Zerys for freelance writers to assist with blog posts, ebooks, whitepapers and other pieces of content and Twitter for following trending hashtags.
#1 Social media channel for content marketing
Since content marketing runs the gamut of long-form, visual and snackable they can all bring different benefits. As far as getting content out there to the most people, I think Facebook wins due to their sophisticated advertising platform. For business related content, it's absolutely LinkedIn.
Long detailed vs short snackable content
There is, and always will be, a place for both to live on the internet. There are so many diverse personalities that consume content in a different way. Some of us are more quick and visual and for us - snackable wins. But, for others who are more analytical, the long-detailed will win. It's always about your buyers and what they will be most appealing to them.
The future of the Content-SEO pair
Just as social media marketing is really just marketing. Content-SEO are now married and I love that search engines are delivering more user-friendly results, so content really does have to be of a higher quality and with the customer in mind, rather than there for SEO purposes.