With the BizTalk Editor you create properties on the message schemas and you can choose either distinguished or promoted properties. So what does that mean, and when do I use versus the other?

Distinguished fields/properties

Commonly used with: Orchestration

Example use case: A decision in orchestration made on some content in the document. Make that content a distinguished property.

Notes:

- These properties do not participate in routing

-  There is no restriction on the length of a distinguished field.

- Distinguished fields are not defined in a separate property schema

- Standard pipeline components ignore distinguished fields but custom components can access them through the “http://schemas.microsoft.com/BizTalk/2003/btsDistinguishedFields”  namespace using XPath on their name

Promoted Properties

Commonly used with: Routing

Example use case: when a message is published into the message box route all messages with the name element = "Great Plains" to the Great Plains adapter and into Great Plains

Notes

- These are used for publish and subscribe routing in the messagebox

- They are restricted to 256 characters

- Create a separately maintained property schema

- Are more restricted in the XSD types supported than distinguished properties

When do I use which?

In general you should use a distinguish properties as they are more lightweight unless you are:

- Routing

- Tracking

- Correlating

- Driving built in pipeline component behaviour

which of course could be all the time depending on your scenario :)...