Official site

• http://www.djangoproject.com/

Comments:

• Great if you want a Python-based full stack framework.
• Works less well if you don't always use an RDBMS
• Very strong form handling capabilities 
• Has many pluggable open source applications

Start-ups using:

• Playfire
• Smarkets
• IvyLees
• BonjourParis
• Urban Alarm