As you can see from the recent March 2011 CTP of WCF Data Services, OData continues to evolve.
While the post includes information about changes to the WCF Data Services implementation, I'm very excited to see that the protocol is also very much alive and well. From the first bulleted list, here are the OData changes you can try out with the new bits.
- Multi-Valued Data Types
- Named Resource Streams
- PATCH Requests
- Prefer Header Support