From TheHatedOne, based on the LINDDUN Threat Model
This gist is a summary of TheHatedOne's tierlist of different messengers; it's here because someone needs it.
Each messenger is scored across 7 privacy threats, each split into 3 vectors: A = Account | U = Usage | S = Service
β= threat mitigated (+1)β= threat introduced (β1)~= partial/neutral (0)