I've been attending the SAP TechEd in Las Vegas conference for the last few days. Overall, I'm impressed with the reality of the story that SAP has put together. In the past, SAP had a SOA-by-PowerPoint story. Today - they have real products and guidance.
At the core of the SAP SOA story is the Enterprise Service Repository (ESR). It is actually a combination of both registry and repository. The registry is a UDDI 3.0 implementation and has been tested to integrate with other registries such as Systinet. But the bulk of the work is in their repository. Unlike other commercial repositories, the first thing to notice is that SAP's is pre-populated (full, not empty). It contains gobs of information on global data types, schemas, wsdl's and similar artifacts relating to the SAP modules.
Both the registry and the repository are designed to embrace service metadata that is housed by SAP as well as service information that might be in other platforms (IBM, Microsoft, etc.) And although the registry will do metadata interchange with other registries, we're not so lucky with the repository. Apparently the current version is designed to be a single instance across the entire enterprise. Of course, this isn't realistic in most organizations due to mergers & acquisitions, etc.
SAP has also customized the TOGAF enterprise architecture to meet the needs of large customers. I was hoping to learn more on this but the speaker failed to show up (bummer). However, it was clear that SAP is relying on IDS Sheer to supply EA modeling tools.
I felt like SAP really got it. Unfortunately, I felt like most of the people at the conference didn't. The gap between vendor and customer has grown significantly. Many of the SAP customers have avoided technology topics, favoring black box implementations of large monolithic applications. SAP is introducing a fundamental change that will take time to sink in. They are doing a great job of evangelizing and providing community guidance but this is a huge leap for many of the 'ABAP' programmers of today.