It’s the biggest video game marketplace/launcher/DRM makers for PC. If you play video games on PC most games you buy would probably have to be through steam. Their parent company, Valve, is the only multi-billion dollar company I like because so far they have stayed pro-consumer.
I guess it depends on what you consider artifacts. 7% of every human who has ever lived is alive today. You can say many of the things people have owned are lost and some might be valuable to someone in the future. So much of our lives are online. I wonder how much of it will survive 100 years.