Once I started doing this I found HN comments would grow off HN. Now there are a few subjects where I can just point people at a link the next time a subject comes up. And the link has often grown out of repeated iterations of debate on HN and elsewhere.

It doesn't bother me that people forget HN comments. I don't forget them, and that seems the important thing.

You _are_ right that one needs to keep HN at arms length. Over the years I try not to engage in repeated back and forth. I'm not writing primarily for whoever I'm arguing with. I'm writing for the silent readers.