Dmitry Medvedev or sales on 3-Ways from Skyline Chili. So, I'll go with the writing folks...
An SFF writer with a keen eye on industry ... and not just publishing. He's a "futurist" who intelligently comments on everything from global solar innovations to Kindle Unlimited's impact on eBook sales. His blog is part of my regular weekly reading: http://www.tobiasbuckell.com/blog
They're the SFF & Horror imprint for Orion Publishing out of the UK. I call out these guys for being a publisher who gets the whole social media thing and how to use Twitter well. They don't just plug sales links; they'll post anything from STNG clips to "Guess that passage" games. Most importantly, they engage with their followers. If you want a good example of how to use Twitter as a business, follow these guys.
an SFF author with a stash of How To Write books rounding out his book
list. His style is distinct and probably not for everyone. (If "fuck"
makes you cringe, don't look. Better yet, run away.) When he's not
amusing his audience with the antics of his toddler, Chuck weighs in on
hot-button issues like gender equality and professionals behaving badly. His blog offers everything from writing prompts and contests, to best practices and public chastisings: http://terribleminds.com/ramble/blog
Victoria Strauss is a priceless resource for helping authors CYA in the publishing world. From shady presses to NYC kerfuffles, Victoria presents well-researched issues in layman's terms. When she throws the flag on a business, pay attention. She's also on Twitter as her author persona @victoriastrauss. The Writer Beware Blog is here: http://accrispin.blogspot.com
I fucking love science
Science...the final frontier... The name is self-explanatory. The reason to follow is for the news, tidbits, breakthroughs, and DYKs Elise reports that spark one's imagination. Since I'm not remotely tapped into any of the many science communities, I like the "Science Lite" newsletterish feel of her posts and her website IFLScience.
I don't know any of these folks personally, I'm simply one of the many who tune in for what they have to say. I like to follow people who can teach me something and/or who make me think. I don't always agree with them or with what they report, but I do like the mental exercises.