The reference implementation should implement the Activity Streams REST API from the OpenSocial 2.5.1 specification with the difference being that the data format being used will be Activity Streams 2.0 instead of Activity Streams 1.0. See links below.
There should be a data access interface with a default binding to MongoDB. The data access abstraction should be generic enough to allow a variety of data sources (RDBMS, APIs, file system, etc)
There should be a page you can visit that will let you pull up activities as a stream and display them in a clean and simple way. There should also be a simple form that allows you to submit new activities.
The implementation should also make use of OpenSocial/activitystreams.js project
This can form the basis for future work and experimentation.
We need to create a lightweight "turnkey" express.js activity streams 2.0 server with a Bootstrap or some other standard application front end.
Activity Streams 2.0 data format http://tools.ietf.org/html/draft-snell-activitystreams-07
Activity Streams REST API specification http://opensocial.github.io/spec/2.5.1/Social-API-Server.xml#ActivityStreams-Service
This can form the basis for future work and experimentation.