[082349872349872]

One obvious alternative: eschew push for as-high-as-practical latency automated pull.

[olliej]

Pull does not solve the problem. The attack here is the metadata "what was the origin" and "what is the destination", and pulling data does not solve that.

[tyingq]

There was some discussion on techniques to get around that in this HN post about a messenger type product: https://news.ycombinator.com/item?id=37105477

[082349872349872]

Sorry, I thought the problem was that the pushes were going through Apple's and Google's systems, which direct pulling would avoid.

How about messaging via wide-spectrum dead-drop hopping? (redundant array of inexpensive drops?)