Article author here, your question is actually a really good one as I'm a bit of an Nginx newb and your comment had me wondering that too. However for the past few hours since this article has been shared the hits have gone quite crazy according to the Raspberry Pis access.log, and the Pagekite.py process is constantly around 30-70% CPU usage, implying a heavy load as normally it uses nearly nothing. Does Nginx reverse proxy cache by default? I'm assuming not given my current results.