Does Django scale?
Another example is rasp.yandex.ru, Russian transport timetable service. Its attendance satisfies your requirements.
I'm building a web application with Django. The reasons I chose Django were:

I wanted to work with free/open-source tools.
I like Python and feel it's a long-term language, whereas regarding Ruby I wasn't sure, and PHP seemed like a huge hassle to learn.
I'm building a prototype for an idea and wasn't thinking too much about the future. Development speed was the main factor, and I already knew Python.
I knew the migration to Google App Engine would be easier should I choose to do so in the future.
I heard Django was "nice".

Now that I'm getting closer to thinking about publishing my work, I start being concerned about scale. The only information I found about the scaling capabilities of Django is provided by the Django team (I'm not saying anything to disregard them, but this is clearly not objective information...).
My questions:

What's the "largest" site that's built on Django today? (I measure size mostly by user traffic)
Can Django deal with 100,000 users daily, each visiting the site for a couple of hours?
Could a site like Stack Overflow run on Django?