I've been blogging for about 16 years. Writing is an underrated way to cement what you learn any given day or year, and over time has made it possible to reach into any part of the industry and get an actual response. Writing is particularly powerful in combination with actually doing things that (are perceived to) matter; the credibility from doing both is much higher than doing either.

Concretely answering the questions asked:

1. At various points I spent a lot of time maintaining, but now it's just a static blog deployed via Github Actions onto a Github Page. I haven't done any meaningful changes in a few years, and the changes are for fun, not necessity

2. I got my first job in tech thanks to blogging: https://lethain.com/datahub/

3. My blogging has made it possible to write two pretty successful books: https://staffeng.com/book/ and https://press.stripe.com/an-elegant-puzzle (working on a third now)

4. Hard to assess, but I believe I've been able to subtly but meaningfully advance the technology industry through my writing :-)

5. A significant majority of folks are unaware that I write, and that's great! I don't think impact depends on folks connecting their colleague to the writer or whatnot