Making digitised content available for searching and harvesting

I have been invited to give a short presentation to the JISC Digitisation Programme on Friday, giving an overview of different ways of exposing content and metadata. I'll be talking to projects which are concerned with Cultural Heritage content which is being surfaced in websites to support eLearning. Formats vary tremendously. This is the complete list:

Aside from the obvious stuff like OAI-PMH, Google, RSS, what should I be talking about? Persistent identifiers? Cool URLs? Any other suggestions?