Contexts can be used as transparent gateways. The persistence context is similar, but actually converts the file contents into a value, which may itself be a context. A context could also access a database, e.g. via dbm. Contexts can get data from another process, data across the network, data on the web, etc. The point is that all of the complexity is handled invisibly, just by using names, not individual protocols.
Gateways can communicate with other languages.
This allows Boa to transparently share data with a Tcl program. This would automatically give object-orientation to Tcl, or some other scripting language, as well as the ability to access a database, the web, or any other contexts available in Boa, just by using certain names. Contexts can be used for synchronization of processes. For example, a semaphore context may suspend processes which request a missing name, until some other process defines a value for that name. When a process retrieves a value, that name becomes unbound again.