This project was the most successful kickstarter in RPG history, and its success was based entirely on Colville's youtube following. The time's they are a-changin' in the RPG world.
He has done tons of GM advice videos on Youtube, now he is going to do some livestreaming of games. A big part of why this kickstarter blew up is surely due to his fans, at least at first. I've seen a couple of his videos and they were fine but I am not exactly clamoring for more otherwise I would just buy the book to support him. I like hardcovers and fancy ones are even better, so I am still deciding.
I enjoy Colville's DM advice. There's nothing especially ground-breaking for an experienced DM, but he presents it in an enthusiastic and engaging way. And it's nice to see a DM who takes an old-school approach to D&D attract such a following of new gamers.
However, I have no interest in the book, and even less in the streaming. On the extremely unlikely chance that PCs in a campaign I run make 10th level, I have a pile of adventures I've never been able to run that are moving to the front of the cue, not stronghold and domain play. And I just don't get live streaming of D&D play. I find even a highly polished and produced stream with voice actors, like Critical Hit, to be dull, pointless, and vaguely embarrassing. I can't imagine anything less appealing than watching Colville and his co-workers play D&D for four hours.
But to show how prominent and influential D&D streamers are today, a couple guys in my group have pledged for the book. And they're not even DMs.