There are loads of good marketing sites out there but for YouTube insights, trends and ideas these are a few favourites worth a read.
Write a really smart and insightful Blog looking at what audiences watch and why.
Latest stories on the video industry about deals, talent and events
The name might sound a wee bit dry but this a gem. Great for stats, analysis and useful Channel tips - in handy videos! (what else?!).
News, industry (mostly US). Publish a top monthly stats chart - useful for finding growing channels an seeing examples of brand partnerships.
Also known as "NRM". The industry stories on the YouTube stars you really need to know about. Features a Tuesday post on collaborations (US focus)