Stable multi-threaded programming (Roxen has been multi-threaded since 1994).
Mostly written in an interpreted, object-oriented, language - Pike:
Easy to program and extend. Just imagine if you could code extensions to the Apache core in PHP or Perl. .:: vnbit.org ::.
No buffer overflows, segmentation faults or any other problems of that nature. .:: telegra.ph ::.
RealNetworks is still using Roxen 1.3 as their main web platform for its stability and speed. .:: vuf.minagricultura.gov.co ::. [Web Specs: Natural language processing]
Low level API available for end-users.
RXML tags.
Lots of modules.
Backwards compatible with Roxen 1.3.
Different. If you are a Linux or BSD user for some time you already know the most used is not always the best. [Wiki: PowerShell] .:: mentorship.healthyseminars.com ::.
Caudium won't run under win32 (thus letting us more time for useful things). However some people are trying to port it using cygwin without code modification.
Embedded PHP4 support.