Strings are the most basic kind of Redis value. Redis Strings are binary safe, this means that a Redis string can contain any kind of data, for instance a JPEG image or a serialized Ruby object.
I am confused by this comment. In the PostgreSQL protocol, everything is a string if you use the text protocol, but you can also use the binary protocol, in which case there is a reasonable binary storage format for hstore. It is even more confusing, as whichever protocol you use seems like an implementation detail of your driver: at the level of an application you should only be working with dictionaries.
