Thanks! We have considered using HLL, and it's a pretty cool algorithm. For us, however, it's important to get the set members at the end of the day. Amplitude

Thanks! We have considered using HLL, and it's a pretty cool algorithm. For us, however, it's important to get the set members at the end of the day. Amplitude is unique from other analytics products in that we put a lot of emphasis on the actual users that correspond to a data point on a graph -- one of our key features, Microscope, is the ability to view those users, see more context around the events they are performing, and potentially create a dynamic cohort out of them. As such, approximations that don't allow us to get the set members don't quite satisfy our use case.