StackShare uses HAML
Personally, I really like HAML. Not having to use open and close tags is a huge time saver. As a result, writing markup with HAML is much more pleasant. HAML essentially forces you to be very strict about spacing, organization, and structure. It also makes the markup easier to read. Protip: I use this pretty frequently: htmltohaml.com
Marc3842h uses C++
C++ is used in Shiro (https://github.com/Marc3842h/shiro).
C++ is a high performance, low level programming language. Game servers need to run with fast performance to be able to reliably serve players across the globe.
OnlineCity uses C++
The most latency sensitive parts are written in C++. Due to our interconnected services architecture, we use either Python or C++ for each service, with the performance critical parts being C++14.
POROWNEO.PL uses C++
Used to write PHP extensions - AZTEC Decoder - License Driver scan - Axis2/C to PHP wrapper and Job-scheduler - Barbershop
LucaFulchir uses C++
Performance, zero-overhead abstractions and memory safety of the modern C++ language make this the perfect language for the project.
ApertusVR uses C++
The main programming language of ApertusVR. C++11 & CMake provides multi-platform targeting. The architecture is modular.