PERL and ASP
, in that order, are (IMHO) the most popular scripting languages that are in use, with PHP gaining.
has the history of being one of the first, widely used server-side scripting languages for the web. You can go to any archive and PERL scripts will outnumber ASP by almost 2:1. A large number of web sites use legacy PERL scripts for a variety of intranet and internet applications.
has been the commerce language of choice due to the heavy use of Win NT/2K infrastructure in many large coporates. Also, ASP provides easy intergration with exisiting MS SQL and Oracle databases. The IIS-ASP-SQL combination is hard to beat when trying to tie both non web and web applications into the same database.
Coporate, Small Business, and Casual
Many coporations rely on proven standards, e.g. Python, PERL, ASP, and Java, for their web hosting needs. There are a few other languages creeping into the market place, but these languages dominate. I worked with a couple of international companies that rely on highly optimized mod_perl to run their e-business.
Personal web sites, small business and others tend to use canned scripts -- these are much easier to set-up and install using PERL and more recently PHP. Most shared hosting solutions require you to use PERL or PHP scripts unless your using IIS. Only with co-lo or dedicated hosting can a small business use alternative scripting languages.
PHP is gaining ground quickly. From Netcraft:
The PHP module is compiled into the Apache server on over 5 million web sites, or approaching 40% of all Apache sites.
I imagine that both PERL and ASP will continue to dominate over the next few years as they represent the installed base. Re-writting customized PERL or ASP code to use a new language is very expensive in the short term -- even if it means savings in the long run. With many dot.coms closing their doors, "long-term" is not in their vocabulary.
That's my cent worth......