For a special meeting of [Portland Perl Mongers](http://portland.pm.org) on Friday, Stas Beckman talked about mod_perl 2.0. He talked for three hours and only went through probably half of his slides.
He went quickly through the difference between mod_perl 1 and mod_perl 2 but he demonstrated a lot of the new mod_perl 2 API. He went through most of the API, all the different stages and handlers that mod_perl can hook into.
Some of the things he mentioned, like protocol handlers and filters can only be done with Apache 2 and mod_perl 2. I suspect it would be possible to write an FTP, SMTP, or XMPP server in Perl using mod_perl 2. I know people are doing things like that in C modules but I think it would be much easier to do in Perl. The other interesting idea I had was to combine POE with mod_perl and use POE to help implement the protocol handlers.
Hopefully, now that mod_perl 2 is officially out that lots of systems will get ported. I was hoping to hear how the Mason mod_perl 2 support was coming but Dave Rolsky left early.
The one thing missing from Apache 2 is some way to separate the Apache children by virtual host and run them as different users. This would make mod_perl much more acceptable for ISPs which could isolate different users but still give them the performance and flexibility of mod_perl. One big advantage of PHP is that it is easy to support shared hosting.