How stable is that link? I fell into the trap of using references to the Perl docs on perldoc.org for a while as they were more up to date than those on PM, but it was a mistake. Initially, the site was fine, but after a short while it became flacky, spending more time down than up. And then it simply disappeared.

It was not really about perldoc vs PM as much as about the appearence of "perldoccmp", to which I guessed you would prefer something more informative, like "cmp (described in perlop)" or "cmp (described in perldoc perlop)". Then direct the link to the resource you like most. I suggested a more compact form, but that was just a possibility.

Of course I always stick to perldoc because I've seen it advised in several places the recommendation to favour it. Yes: you're right that it is a little bit unstable. But it doesn't seem to me that it has disappeared. Indeed it's working for me now.

Of course, if it was possible to produce properly indexed HTML using pod, we be able to link directly to the section of perlop entitled "Equality operators", which would be a significant improvement. But that ain't gonna happen anytime soon.

Well, within perldoc.perl.org you can directly link to sections like that: Equality Operators.