What other aspects of governance work well?

I'm still learning how to do it, but I think there are several key pieces in governance. One is to have a registry or repository of services so that you can publish and keep documentation about the services that you're building. The architecture review board is another important piece.

Another big piece is having an examples library of services that we think work particularly well. That's been almost more powerful than anything else here. People ask what a good service looks like, but the examples aren't just code, they are a library of every artefact throughout the whole lifecycle. So what does the design look like? What does a test plan look like?

Another consideration is when you're introducing a lot of middleware technology to enable SOA, you don't want every part of the company going out and figuring out how to best implement those technologies independently. You want to coordinate the configuration of your middle tier centrally, not just to support the application, but to configure it for the best performance and operability.

SOA veterans say it's difficult to determine the right level of granularity for a service — what should be included within it and what shouldn't? Can you offer examples of how you approach this?

Sure, let's take billing as an example. We have a coarse-grained service called "charging", which includes everything from billing and taxing to bill presentment. Each one of those has its own composite service.

What we're trying to do is make sure that people are consistent in how they implement services.

A fine-grained service within "charging" might be "accounts hierarchy". I'm going to let an individual team manage that service rather than taking it to the architecture review board level.

What's the ROI on all this?

The big savings is time to market. For example, in the provisioning process, the ability for us to create a new product or a new flow in the provisioning engine is measured in days and weeks rather than in months, which is how long it takes in our non-SOA-compliant application.