Certainly a beginner could learn this stuff right away, but I wouldn't consider it inherently beginner-oriented. Personally I don't think one canonical tutorial or reference is as effective as a large number of articles focused on things that different individuals find useful. Vim is just too big to absorb through one gargantuan tutorial.
My guess is that it's a combination of a) a lot of people are learning Vim right now and b) a lot of these people have blogs.
Coming to Vim from some other editor is an awesome experience for them and they want to share.
I know: I've been using Vim daily since one year now (coming from TextMate) and I've posted 20+ random tricks as I learned them. I'm currently drafting my "one year with Vim" post.
I think that one person could have found the information from an existing source, such as _:help text-objects_. That isn't to say that the article is useless; it's just redundant.