Now that we have an understanding of both SQS and SNS, let's see how we can apply them to our sample application Waaah. If we look back at the previous chapter, we saw that our sample application was composed of three parts, an SQL Server Database, a WCF Web Service for subscribing and unsubscribing to widgets, and a MVC web application.
In our current architecture, there is only one way to subscribe/unsubscribe to widgets for our Widget Company, and that is through our MVC Web application, Waaah.

While this was the initial design choice for this application, wouldn't it be great if—now that we have migrated our sample application to AWS—we could open up the Subscribe/Unsubscribe service to other applications. So let's look at how we would integrate these two services into our sample application Waaah.
Firstly, let's decouple the WCF Subscription Service from our Subscribe/Unsubscribe service by placing SQS between them. Then let's add another...