It's been a busy week with both the AIIM show and RTM hitting MSDN. I decided to stop working on any more posts until I got RTM running in case anything changed from my previous build. Order is beginning to be restored though and I've started three different posts, which hopefully will all be done this week. If you'd like to read my previous posts on the ECM Features That Rock in SharePoint 2010 you can find them here:
ECM Features that Rock in SharePoint 2010: Enterprise Managed Metadata Part 1
ECM features that Rock in SharePoint 2010: Enterprise Managed Metadata Part 2
ECM Features That Rock in SharePoint 2010: Business Connectivity Services Part 1
ECM Features That Rock in SharePoint 2010: Business Connectivity Services Part 2
ECM Features That Rock in SharePoint 2010: List Validations
This should be one of the simpler feature posts as Documents Sets are very straightforward and easy to implement. With SharePoint 2010 (not SharePoint Foundation) a new Parent Content Type is available called Document Set that allows many documents to be grouped together into a single working set. Document Sets are made up of any number of Content Types which determines the types of documents that can be contained within it.
Properties of a Document Set itself are unique from the actual properties of each document in the set. Users with appropriate permissions can modify the properties of the set or of each document separately. However properties from the set have the option of being automatically pushed (synced) to each individual document within it. Since the set itself is its own document it can also be versioned and work flowed.
Turn It On
To start using Document Sets the features will need to be activated. Select Site Action | Site Settings:
Documents sets are a site collection features, so in order to activate these features select Site collection features and then activate it:
Creating Document Set Content Types
Once activated the Document Set Content Type will be available. I recommend that new content types based off Document Set are used to see the true power of document sets.
Go back to Site Settings and select Site content types:
Select the create button: 
Fill in the values for the Name and Description by using Document Set as the parent content type.
Once the new content type is created the information page will be shown. There is Document Set settings link that is unique to content types inheriting from Document Set. After adding any columns or other needed configuration select it:
The first section of this page is Allowed Content Types. Use this section to add the content types that can be added to this document sets of this type. The second section is Default Content. Adding default content will force the creation of a new instance of the file to be added ever time the document set is created. To use a content type here it must first be added to the Allowed Content Types.
The next section is Shared Columns. This forces specific columns in the set to be synchronized with columns within documents in the set. If a column is not checked the documents within the set are allowed have their own values. This will only work if the content type of the document being added to the set shares the column with the document set content type itself. That's a mouth full and I apologize.
The Welcome Page settings are self explanatory. Just setting up which columns are shown when viewing the document set in SharePoint.
Using Document Sets
Once a document set content type has been created it can be added to any Document Library in the site. Once added a new document set can be created. From a Document Library, select the Documents tab.
Select New Document and then select the document set to be added to the library:
Fill in the necessary properties and select OK and a new document set will be created and the welcome page will be displayed. At this point new documents can be created or uploaded to the set from the Documents tab just like above. Any content added however will be added to the set and not the root Document Library. The Library tab next to Documents however, is referring to Document Library settings itself. To manage the set itself use the Manage tab underneath Document Set.
There are many uses for document sets and going into each one would be much too cumbersome assuming you've even read this far. Uses that quickly come to mind are employee packets, loan documents or any group of documents that typically gets routed as a whole.
One correction I do need to make for anyone seeing my previous presentations on document sets is the ability to download them. Although allowed in the beta, downloading documents sets does not seem to be possible in the RTM. At that time they downloaded as zip files and if anyone figures out how to make this work, please leave a comment letting me know how.
KnowledgeLake
At KnowledgeLake we have already built the ability to use document sets into the new Imaging for SharePoint 2010 product. When opening a document set or any document contained within a set in our Silverlight Document Viewer an option to open something we call the Document Set Explorer will be available. This will allow users to see each document in the set with the ability to open it inside our viewer.
We also plan on adding new capture features around document sets later this year. These should be available in both KnowledgeLake Capture and KnowledgeLake Connect and will have features such as capturing directly into document sets.
Thank for reading.
-Chris Caplinger