Continuing this discussion, I have just finished a simple web app on Django and was surprised that it scored 88/100 on Google's Pagespeed . So I researched on who was brave enough to deploy Django on a large app and behold, Disqus. They even have a Pycon presentation on their experiences http://www.slideshare.net/zeeg/pycon-2011-scaling-disqus-7251315 .