It introduces a nice level of indirection between different actors, so that they don't need to know about each other's existence in order to communicate and solve problems together. The actors can be added and removed dynamically, and so the problems to solve and the problem-solvers can evolve over time. It's a pretty powerful and flexible idea! To use GoF terminology, it's like having a Mediator for a bunch of asynchronous and fully decoupled pub-sub Observers and Observables. It's a way to implement Barbara Hayes-Roth's Blackboard model.

JavaSpaces, TSpaces emphasized the over-the-internet aspects of it, which didn't matter to us for our project. We ended up finding and using something much simpler called LighTS. With all the nice support for concurrency in Java these days though, it wouldn't be much work to put one together from scratch.