The Nginx changelog for the 1.0.9 release (on November 1, 2011) had a single line note tucked away inside:
*) Feature: decrease of memory consumption if SSL is used.
So why am I even blogging about this? This site surely isn't big enough to have this really make a difference, but the before and after on the graph of Nginx memory usage on the Arch Linux forums and wiki server is rather astounding, a site that does only HTTPS. If you use Nginx + SSL, I'd highly recommend upgrading.