[enraged_camel]

>>- Want to write contacts? Here's reading too! Want to write texts? Here's reading too! Same as above really. Is the use-case of wanting an application to be able to add to my data (at my request) but never-ever read all my data really that hard to predict?

I've configured security for a large variety of systems and I've never heard of a write-only permission. Read-only is often seen as a lesser right than read-write.

[victorNicollet]

I'm sure you've heard of the UNIX sticky bit, which is used so that anyone can write a new file to `/tmp`, but without being able to access other files in the same directory. I can certainly imagine the same implementation for contacts (create new contact, see only contacts you have created) and texts (create new text, see only texts you have created).

[azernik]

It's more like append-only in all of these cases - think of the things you want unprivileged processes to be able to do to your logs, for instance.