The tutorial presented an easy approach to start a web application with Couchbase Server 2.0 as the underlying data source. If you want to dig a little bit deeper, the full sourcecode on couchbaselabs on GitHub has more servlets and code to learn from. This may be extended and updated from time to time.
Of course, this is only the starting point for Couchbase, but together with the Getting Started Guide, you should now be well equipped to start exploring Couchbase Server on your own. Have fun working with Couchbase!