Long story. Older hardware, doesn't do flashy stuff, helps stop me procrastinating, runs lots of low priority, background tasks that will get broken by upgrading, and so on.

The fast, whizzy machines with new OSs and up-to-date browsers get used for serious, work-related stuff. Not for HN.

Hasn't Firefox 1.5 lacked security updates since it was discontinued ~4 years ago? Why not Chrome or something?

Yes, true, but I don't go click on much. Anything potentially interesting I actually forward to another machine that's more secure and look at it there. There really isn't much joy in trying to hack that older machine.

It's so old, most attack vectors don't work anymore anyway. And I have other protection in place that I won't discuss.