[msiebuhr]

Facebook does this (and quite a few other tricks) for storing time-series data in Gorilla (in-memory TSDB, Paper: http://www.vldb.org/pvldb/vol8/p1816-teller.pdf), getting to 1,37 B per sample.

Prometheus implemented the Gorilla-bits (see https://prometheus.io/blog/2016/05/08/when-to-use-varbit-chu...) and reports getting down to 1,28 B per sample on some workloads, though at a cost of increased query-latencies.