You can find the full source code for this website in the Seam package in the directory /examples/wiki. It is licensed under the LGPL.
Seam established the concept of conversations, which then CDI adopted. In parallel, JSF 2.0 was specified as JSR 314, with a long discussion whether conversation scope was worthwhile or not. Finally it was agreed on a compromise (Flash- and View-Scope), but a Conversation scope was not specified.You must use CDI if you want conversations with JSF 2