David Linthicum in his blog post defines the problem SaaS consumers faced with.
Sometime it's very important to think as a customer. So what he writes:
"When planning to integrate your SaaS applications, certain things need take place. First, you need to define the information you need to integrate, what it is, who owns it, and how it's accessed. While most SaaS vendors have APIs or Web services to support integration, many of these interfaces are not well thought out or are limited in some way. Next, you need to define the interfaces and information on the enterprise applications side, answering many of the same questions. This means you should have a semantic- and interface-level understanding of the integration domain, including all systems connected, SaaS and non-SaaS."
A good case comment. It must be owned we often do things nobody particularly needs. And that's a pitty.
The article can be found here.