I do follow the steemiblog, and since they've pushed out more information in the last several weeks than they were prior, it's been a beneficial follow, except at some point there needs to be the actual stuff they're updating us on dropping, rather than just more talk about it.
I don't follow the other two, but I've seen really good things coming out of them. I just tend to have my attention elsewhere. I suppose I should take some time to investigate those two at some point. :)
Honestly, I wasn't explicitly "following" 2/3 of these blogs prior to writing this. I knew about them, I'd read some of their blogs, but that's it. That being said, after reading a few of them I decided to start following, as they provide articles on topics that are of high interest to me.