The Django Web application framework made to help you build websites fast offers a session storage mechanism that does not allow a visitor to fully terminate their session when they log out. Though not the default storage mechanism — as is the case with Ruby on Rails — it is an option. I found that at least Pinterest and Instagram use this vulnerable option to handle sessions on their websites and I demonstrate what the issue looks like to a normal Web user in my video:
Pinterest.com and Instagram.com both suffer from WASC-47, OWASP Top Ten A2, and CWE-613. The situation is especially bad given the lack of SSL protecting the transport of the permanent session cookie/token between their servers and your browser.
To identify additional high-profile Django-based websites that might use the vulnerable cookie-based session storage mechanism, here is a starting point: http://stackoverflow.com/questions/1906795/what-are-some-famous-websites-built-in-django
Happy hacking! Contact me with questions.