Screenshot + OCR seems tough, but sounds like it could be your preferred workflow. More robust will always be 1. a link to the article/thread and 2. a transcription of the content (esp. tailored to you [1]) imo. Your search term idea is interesting, I know Google is/has been doing this.
Physical notes are great for the reasons you mention - I tend to transcribe my physical notes into e.g. Google Docs/Dropbox which seems to make it easier to refer back to them. Of course you run into potential privacy issues for sensitive notes; on that front, pen and paper notes (or an offline machine) are hard to beat.
