Here’s my take on this:
I will split this into two topics: versioning and discoverability.
I remember when me and some colleagues set about learning Python and machine learning and encountered the same problem, but much more severe: tons and tons of blogposts and tutorials which we never got working because they haven’t even documented if they used Python 2 or 3 (we were absolute beginners and had no idea about the differences). This is the perfect example of more “documentation” means “no documentation”.
Actually I got so frustrated with the Python situation that I convinced all of them to switch to Julia:)).
And yes, there was way less documentation, but what we found was good and got us going very fast.
This experience taught me that “google it” is not always the best approach and most beginners use this method for getting something going fast. I learned to rely more and more on the official github documentation (something I never imagined existed, being primarily a Matlab user), so here I agree with your three main sources of information. Of course some of the github documentation might be outdated, but there is not much to do about it other than submit and issue or PR. I’m always very grateful when I see even minimal documentation on github packages, given the amount of work invested there.
The takeaway for versioning: this problem is not Julia specific and simply educating the blogpost authors to post their package versions used (or better, provide a github link with the project and Manifest.toml) would be very helpful. (this could apply also for youtube tutorials)
Regarding discoverability, I really like Get started with Julia and https://juliahub.com/. Pinning these would do no harm. Otherwise newcomers will search blindly on google and probably find an outdated tutorial or package.
I don’t think it’s possible to have a Documentation category containing hundreds of links to documentation (it would be very hard to maintain as well, and we have juliahub which is awesome).
But I agree that a Documentation category containing some links like the two above would be useful(or maybe pin a post with such relevant links in First Steps?).
I wonder if there are any statistics on how many people visited the julialang learning page vs. how many visited discourse.