Free and Open Source Software

There's a large difference between surrendering massive amounts of highly critical metadata aswell as some data* to a known abuser vs. an entity that prides itself in not abusing your data and which even takes specific technological measures to make it as hard for them as possible (zero access encryption at rest, automatic key discovery).

(* Partial social graph, interaction timestamps, political interests, health, hobby interests and much of that usually even in plain text data form when receiving email; stored in in plain text forever.)