Who uses Mercurial
Mercurial is a free, distributed source control management tool. It is currently used by many Open Source Projects such as...
MozillaMozilla is an open source project that is currently developing the popular Firefox internet browser, the email client Thunderbird and the application suite SeaMonkey. Mozilla chose Mercurial in 2006.
Java / OpenJDKOpenJDK is the official open sourced Java implementation of Sun Microsystems. When open sourcing the project, Sun chose Mercurial as their main version control system.
NginxThe nginx web server is among one of the most popular and used over the world.
Not just Mozilla and Java use Mercurial. A lot of projects of various sizes have decided to use Mercurial for its efficiency and power. A longer list of projects which use Mercurial can be found in the wiki.