Also, anything you do with enterprise (cloud) customers. People like to talk about scale a lot and data people tend to think about individual (distributed) systems that can go webscale. A single system with many users is still a single system. In enterprise you have two additional types of scale:

1) scale of application variety (10k different apps with different needs and history)

2) scale of human capability (ingenuity), this scale starts from sub-zero and can go pretty high (but not guaranteed)