My presentation at yesterday's Toronto JUG meeting covered a lot of ground as it both introduced RDF and demonstrated how to use RDF with objects. Many of attendees struggled with the significant mind-shift from relational to RDF and how a data model can be represented as a graph of nodes.
One important point, that I want to reiterate, is that RDF stores are not designed as general purpose databases (as relational databases are), but instead RDF stores are designed for complex data structures. Currently, RDF is mostly used within industries that have complicated data models. However, RDF is becoming more appealing to a wider audience as data models in general are becoming more complicated and interconnected.
If you attended the meeting and/or are interested in talking more about RDF. Read through the getting started guide for Sesame and join the discussions on IRC at irc://irc.freenode.net/sesame