Also, I know that for some things that I write about, I'm not actually an expert on it beforehand. Instead, I see an interesting question, say to myself "hmm, that's interesting, and I don't actually know the answer", go out to Google, books I own, or just try some experimentation out myself, and then comment on what I found. I usually do try to provide sources and some details about what I did when doing this, but I realize that it may sometimes make me look like more of an expert on topics than I actually am. For example, I have a silver badge in JavaScript on StackOverflow, even though I've only ever written a few dozen lines of JavaSript in my life (in fact, I've probably written more lines of it on StackOverflow than off), since I tend to be good at quickly researching and experimenting with a question and providing a good explanation, not because I'm an expert on JavaScript.
So yeah, it's great the Julia writes down her thought and search process while doing this, as it helps people realize that they too can go through the same process and learn new things.
So while it appears that everyone here is amazing; that isn't the case: we just tend to have something that we're very good at and comment on it.
The good thing is that you can learn a lot here as long as you don't get sidelined by some of the inane arguments and fighting :)
It helps to try to tackle a project that you don't already know how to accomplish. Then the Q&A can work like a reverse dictionary. You know the answer, and work backwards to find the question. Every stumbling block is a question to ask.