The 10 Most Important Open Source Projects of 2011 https://www.linux.com/news/featured-blogs/196-zonker/524082-the-10-most-important-open-source-projects-of-2011
Nginx
Apache (more accurately, the Apache HTTP Server Project) still rules the Web with an iron fist. OK, it's more like a velvet glove, but Apache is definitely far and away the most popular Web server. But 2011 was a huge year for Nginx, an alternative Web server that excels at HTTP and reverse proxy serving.
Nginx reached a lifetime peak of 8.85% market share this year on the Netcraft Server Survey. According to this profile on Royal Pingdom, the usage for Nginx has jumped nearly 300%.
The little server that could reached another major milestone this year as well. Specifically, Nginx went corporate and started offering commercial support.
It's being used by some of the biggest sites in the world, including Dropbox, WordPress.com, Facebook, and about 25% of the world's busiest sites.