[vhakulinen]

> In my opinion, side projects don't have to ship.

Totally agree. I have had tons of side projects and most of those have just been for fuzzing around with new and shiny (or old and solid) things. From side projects, I have "shipped" couple of apps but have gained the most experience from the ones that I haven't.

Also, the blog post mentions only books and blogs for reading. I've found that reading issue tracker/PR and other forums closer to actual code has sometimes been extremely helpful (in those cases, I tend to end up reading the code it self from time to time).