Like many companies, the software at YC is like an iceberg: most of it lies beneath the surface.
Here are some of the things we build that you might not be thinking of:
https://apply.ycombinator.com/ - the whole process of receiving and processing 10,000 YC applications / batch
https://workatastartup.com - a site to help people find jobs at a startup
https://startupschool.org/ - a free online course in how to start a startup
https://leap.ycombinator.com/ - a private community for women in tech