Does Django scale?
We're doing load testing now.  We think we can support 240 concurrent requests (a sustained rate of 120 hits per second 24x7) without any significant degradation in the server performance.  That would be 432,000 hits per hour.  Response times aren't small (our transactions are large) but there's no degradation from our baseline performance as the load increases.
We're using Apache front-ending Django and MySQL.  The OS is Red Hat Enterprise Linux (RHEL).  64-bit.  We use mod_wsgi in daemon mode for Django.  We've done no cache or database optimization other than to accept the defaults.  
We're all in one VM on a 64-bit Dell with (I think) 32Gb RAM. 
Since performance is almost the same for 20 or 200 concurrent users, we don't need to spend huge amounts of time "tweaking".  Instead we simply need to keep our base performance up through ordinary SSL performance improvements, ordinary database design and implementation (indexing, etc.), ordinary firewall performance improvements, etc.
What we do measure is our load test laptops struggling under the insane workload of 15 processes running 16 concurrent threads of requests.
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?