In July 2014, the maker of a well know launcher for the ARMA 2 mod, DayZ, failed to update his launcher in the wake of GameSpy (server listing service) shutting down and the ARMA developers moved to Steam for server listings.
It was at this point I decided to write a new launcher which used to new Steam system, 7 days later DayZ Launcher was released.
The launcher uses the torrent protocol for primary downloads, the idea here was to reduce bandwidth costs and provide an easy method to verify file integrity.
As of Feb 2015, the average usage over the last 30 days is around 850,000 launcher opens and is gaining in popularity.
A PHP backend support both launchers, scanning servers, detecting mods and dealing with pushing that data to the luncher.