I assumed OP was the website owner. But while my request is serious and legally binding, it was somewhat rhetorical as I do not expect the owners of a site with such a data policy would really be conscientious about contacting me to sort out which data is mine and removing it.
> But while my request is serious and legally binding, [...]
Posting a comment on HN is somehow legally binding for a third party website whose operator likely never even heard of HN? Or what are you trying to say?
As I understand it, the request to have data removed is what's legally binding, not the format in which the user makes the request. If the site owners see it or otherwise become aware of it, they are obligated to remove my data even though it was a post on HN. Whether all of that actually happens is a different story. They could probably claim truthfully they don't know which data is mine. If I were determined, I'd contact them directly.
Don't be absurd. I'm a big proponent of GDPR but you seem to be under the impression that it's a magic spell. You seriously believe that, legally, if you post a comment on HN, you're putting an obligation on someone? I have a piece of the moon to sell you, then!
That is a misapprehension of what I wrote.
Also, I threw that in there because, if the site operators were to see "I don't expect them to actually remove my data", I do not want them to interpret that as releasing them from the obligation. It does not. It's just my prediction of how things will go.