Well, the point is to keep that fingerprint isolated to anonymous accounts. I don't mind if anonymous accounts are linked. Luckily I don't write much outside HN, and even less under my real name. I am, however, not under the illusion that this practice makes me safe. It's just something I do out of nervousness, since the only other option is not to write, and I'd rather not give it up.

Yeah, you can't just change from one fingerprint to another - you either have to erase your fingerprint (such that you look identical to someone else), or generate random ones and cycle through them. The anti-web-tracking people have been wrestling with this one for a bit.