In Dojo 1.7 a new way of loading script modules, AMD, was implemented. It changed completely the way of developing with Dojo.
The preAMD code should still be compatible with Dojo 1.7 and later releases, but all the new information, tutorials,.. are written using AMD, that is the new standard in Dojo.
In Domino 9.0, Dojo 1.8 has been incorporated to the product, but, for instance, the discussion template is still using the preAMD syntax to load dojo modules.
You can migrate manually your code, but a new tool, in Alpha version right now, has been provided from SitePen ( Dojo creators) to automate the process. You can find more information in this article: Introducing dojo-amd-converter
“Asynchronous Module Deﬁnition (AMD) API speciﬁes a mechanism for deﬁning modules such that the module and its dependencies can be asynchronously loaded”