Performance
Performance is a feature. Studies show how slow sites have an adverse effect on users, and therefore, revenue. For instance, tests at Amazon in 2007 revealed that for every 100 ms increase in load time of amazon.com, the sales decreased by 1 percent.
Reassuringly, several high-performance web applications such as Disqus and Instagram have been built on Django. At Disqus, in 2013, they could handle 1.5 million concurrently connected users, 45,000 new connections per second, 165,000 messages/second, with less than 0.2 seconds latency end-to-end.
The key to improving performance is finding where the bottlenecks are. Rather than relying on guesswork, it is always recommended that you measure and profile your application to identify these performance bottlenecks. As Lord Kelvin would say:
If you can't measure it, you can't improve it.
In most web applications, the bottlenecks are likely to be at the browser or the database end rather than within Django. However, to the user...