Design question

I am new to scala and actor models.

Yesterday I read a website (http://scala.sygneca.com/patterns/start) talking about patterns. There is one pattern called `Reactive abstractions' which does not have further explain but shows it is related to actors.

My question is when programming using actor models, is there any thing developers need to carefully pay attention to? For instance, I am planning to develop a system which may communicate through network. A server X may propose message to a server Y. After computation, the server Y may response back to the server X. Also, there may have many other server similar to X and Y involved as the system grows.

Considering such scenario, Is there any pattern can be applied? Or is there any article or resource that may talk about such issue?

Thanks for help.
I appreciate any advice.