In my experience, I built a Portal where a Portlet offered an end-user a choice to choose the source of financial information out of the list of providers like Morningstar or Lipper Ltd (A Reuters Company). At the back, I provided corresponding services.

Now, getting into the SOA age of business-centric architecture, I share some concerns about brittleness and vulnerability. However, if one follows the SOA RM standard and avoids ‘bold’ Web Services (initially provided by Amazon, Google and Yahoo!) but, instead, relies on the business execution contexts and Service Contracts that include business responsibilities of the service providers (including security and QoS), the compound application might be not that bad at all.

This means, there should be an intermediary responsible for the quality of offered services and their compatibility. In other words, an orchestration/composition of the services, performed by the user, only looks ‘ad-hock’ while it is very well prepared by the intermediary.

What is about an end-user just composing different services in the Web site? It is absolutely fine; it is called a ‘freedom of choice’. Such end-user becomes the author of the thing we can call a ‘custom application’, s/he is the master and the owner of it. And all problems and concerns are on her/his hands. Exactly as it is in real business life (“it is a simple SOA, stupid”)

- Michael Poulin