Also useful for nginx: adding the pagespeed module https://github.com/pagespeed/ngx_pagespeed "ngx_pagespeed speeds up your site and reduces page load time by automatically applying web performance best practices to pages and associated assets (CSS, JavaScript, images) without requiring you to modify your existing content or workflow."
pagespeed is impressively helpful, great news when nginx support was announced (a tipping point for me), just wish I knew going in that I had to compile for SPDY instead of using apt