MOA vs. SOA

Message Oriented Architecture (MOA)
An architecture for exchanging documents where there is no implied semantics about what should be done with a received document.

• What does this definition mean? It basically means that MOA is for broad-scale information sharing. An example would be stock ticks. A financial services firm will have a MOA backbone to distribute changes in stock values to any application that is interested. It doesn't dictate what someone does once they know a stock has changed - it just informs them that it has happened.
  
• By this definition, MOA is primarily used for data synchronization and event notification. As a result MOA would often be pub/sub based.
  

Service Oriented Architecture (SOA)
In contrast is about execution of business processes through services.

• You are distributing documents with a purpose - you don't send out an order "just because" you send it out because it is to be processed or cancelled. With an SOA the consumer is interacting with a provider for a well defined purpose (e.g. processing an order). The end result is that SOA rarely leverages pub/sub - SOA is more focused on "directed messaging" (messages directed at a specific target for a specific purpose).
  

DPM - The Business Architects @ Quadrobay