The Phusion Passenger guys really dropped a bomb at their Railsconf presentation today, which unfortunately was poorly attended. Their successful copy-on-write improvements to Ruby (released as Ruby Enterprise Edition) and their improved queueing mechanisms in the Passenger Apache module make it currently the Rails deployment option with the fastest execution times and the lowest memory footprint, even when compared with nginx and thin servers in front of mongrel clusters.
On top of this, they announced that the mod_rails moniker has been abandoned, since it now supports Rack (which allows you to host things like Camping and Merb apps) and WSGI, which even lets it run things like Django (!)
I personally am really excited that Dreamhost has installed Passenger, which makes it so much easier for me to host my personal Rails apps.
