I like listening to the talis podcasts because they motivate me to think about semantic-web issues. Unfortunately I usually spend the entire session muttering to myself because I disagree with so much that is said.
The issue for me is that speakers often paint a rosy view of a merged data world where 'if only' people would adopt RDF and share their ontologies, systems would be able to communicate and share data. OWL is commonly painted in a broad-brushed way as the mechanism that would then enable semantic web interoperability. I have my doubts - deterministic ontologies get complicated and brittle very quickly.
Here's a test:
If atom were an RDF format (i.e. same data structure, just in RDF), could OWL realistically be used to allow an RSS1.0 app to interpret atom data?