Being able to look back at things you wrote about 2, 5, 10 years ago is personally fascinating, but it's also a really good way of demonstrating how your skills and experience have grown over time.

I recently noticed I've been writing about SQLite since 2003! https://simonwillison.net/tags/sqlite/

Not OP, but the act of writing not only solidifies knowledge, but creates it

PG has been beating that drum for a few decades, and I’ve experienced it too

And knowledge compounds — knowing stuff makes you learn faster, which can lead to new jobs, friends, projects, etc

I’ve also found it gratifying when undergrads are reading and referencing posts I wrote when they were 13 years old

There’s something very nice and human about that

Likewise I learned a ton from Joel Spolsky’s blog when I was 22