Interesting debate. Perl once dominated the Web, not so long ago (let's say late 1990s and early 2000s, someone can correct me if I am wrong on the exact period), it is clearly no longer the case. I guess PHP is possibly easier to use for Web masters who are not programmers. One of my subjects of interest is photography and I am spending quite some time on photo forums; most of them seem to be based on PHPWebGallery (or Piwigo), Ubergallery, Coppermine, PHPGraphy or similar PHP frameworks or ready-made solutions. My own personal site, created more than 10 years ago and not very much maintained in the last 5 years, used some Perl and Javascript (although it was mostly static HMTL, to tell the truth); I guess that if I was not involved into Perl as much as I am, today, my first idea would probably be to do it in PHP and Javascript today. Having said that, my main centers of interest have moved away from web programming, I do not know Mojolicious or Dancer, so I am not making any comments on them.

And, although I am not personally terribly interested in super fancy looking sites, and much more interested in the value of the content, one must say that the main Perl sites are not very convincing graphically and otherwise, this includes to various degrees in my view Perl Monks, CPAN, Perl Doc, Perl Foundation, Perl Gurus and Perl6, just to name a few. (Sorry if this hurts someone, this is not meant to criticize anyone, I am certainly not able to do better. I just think that there are some opportunities for improvement.)

Now, this is just a personal opinion, very much subject to debate, I may be very wrong, I would be very interested in hearing what other people here have to say on the subject.