Between the SC2 shoutout in the Scaling Disqus presentation, and the name & icon of this, my money would be on the Disqus team at Startupcraft (http://www.startupcraftsf.com).
They have a free trial, so it's only not free after a certain time. Would you say it was free if they had a freemium account instead? The reason I ask is because we've been kicking around the free trial/freemium thing ourselves, and think the freemium accounts are probably seen as a better value to end users.
Not free after a certain time is "not free". It's kind of the worse of both. Free trial feels like scam trick "get them hooked, then when, their dependent rape their wallet." What if I'm not done evaluating when free trial is up? I have to think hard about when to start free trial to make optium use of it's duration. So, I'm likely never to start it and certainly not "right now" when my interest is highest.
Freemium is vastly "superior". Seems fair and of real value. Use this, if you use it so much it costs us "real" money will want to charge you. Use this, if it's all you need awesome, maybe you're just a hobbyist or messing around. But if you're making money and could use these extra features, hey share some of your cash with us.
I always enjoy following the work of David Cramer. He seems to always be involved in large, real-world django environments. It can be hard to find examples of django code that go beyond a simple CRUD blog. Nice work, David.