I use SingleFile to save a copy of every article / post / SO & forum discussion I find interesting or useful. I sort them into two buckets: work, and not-work.
I’ve been doing this for 10+ years (before SingleFile I used things like .pdf, plain .html, .webarchive files - although these all have drawbacks).
In the pre-LLM era, I would then interface with these almost exclusively through a search front-end. I use Houdahspot on Mac and easySearch on iOS. That lets me see everything interesting I’ve read on a particular subject just by typing it in (with the usual caveats that apply to basic keyword search - although in practice that alone has proven very effective). Because it’s just a folder of essentially zipped .html files, there’s no lock-in.
Now that we’ve got LLMs, I plug those 10+ years of files straight into my RAG pipeline using llama-index. It’s quite nice :)