A lot of web 2.0 sites seem very quick and seamless. I was curious as to what programming languages websites like wordpress, flickr, campaignmonitor, etc use, both from the client side and from the server side.
Many use PHP or Python, though many others (like StackOverflow) use Microsoft tools. The client side language is mostly Javascript, though some sites are done in Flash or Silverlight.
Most web2.0 sites use a combination of languages. Some of the most popular include AJAX, Ruby On Rails, Python and good, old-fashioned PHP.
Speaking for WordPress in particular, PHP is the primary language used.
client side would be JavaScript, most of the web 2.0 companies use PHP, Ruby (Rails) and Python..Java and .NET is also used but the biggest players like facebook and digg use PHP while twitter uses Ruby on rails
php, ruby on rails, and python are trendy choices. Some also use Java. Flickr and wordpress are PHP. Twitter is ruby/rails and scala.
It is not about the language, it is about what it does. Basically using some form of Ajax to not do full page post backs.
MySpace - .NET (using BlueDragon)
Facebook - PHP
Youtube - Python
StackOverflow - C#
Wordpress - PHP
Flickr - PHP
Basecamp - Ruby on Rails
CampaignMonitor - Python
Twitter - Scala
You can find out specifics (usually) by plugging some URLs into builtwith.com