Quantity far outstrips quality. Everyone and his dog provides content, our challenge is find the valuable stuff. This makes me incredibly picky about what I subscribe to, hence the short list below.
Each author writes their own content, give their opinion on content from others and provide links to what they consider valuable. They are direct, don’t shy away from intelligent critique, don’t try to sell you stuff and don’t waste your time. Their opinions are their own, not those of an organisation, and, because they care, they often express themselves passionately. Oh and they’re pretty knowledgeable.
It’s important to me that I determine when I read stuff. I do this by using email rules to send them straight to specific email folders. This avoids unnecessary distractions, because it’s up to me when I look in a folder and when I read what’s in it.
I’ll add/remove newsletters and blogs from time to time, but don’t expect frantic activity. All are free.