I've been hacking on the development branch of KOffice to add RDF support. Thanks to KO GmbH for this chance! This means that while a document can posit a linear progression of characters and words like normal, the software can start to understand a bit of what you are talking about too.
The ODF document specification allows RDF to be included in the document zip file either inline in the main content.xml file, or using manifest.rdf and other RDF/XML files in the zip. The RDF is free to refer to XML elements in the content.xml, so you can add metadata to names, places, times etc so that a computer can work out unambiguously what you are talking about. This makes an ODF file a very powerful container format for transmitting meaning to people.
At it's heart, RDF represents all information in triples. Bob knows Alice, etc. See lwn.net or other sources if you want to know more about RDF. But you don't have to know it to use it with KOffice ;)
Below you can see that I've hacked the "Document Information" window to let you see the raw RDF if you want to know exactly what is going on:
If on the other hand, you are not a developer and/or don't really care about triples or RDF, there is the Semantic view. Right now I only have support for Contact information which is drawn from the FOAF RDF vocabulary. If the later doesn't mean anything to you, its just a way to describe people and their relationships using RDF. As you can see, you don't have to care about RDF here, you just see people. Right clicking on a person lets you do things like import them into your contacts database, or, in the future, other things like email them or phone them.
While it is nice to be able to have contact information extracted from the document, it is much nicer to have KOffice know exactly where that information relates in the document. For this I have a new Docker for RDF as seen in the below video. First you see that the addressbook is empty. Then I start moving the cursor around in the document. Notice that the docker picks up when the cursor is on the name of a person that has RDF metadata. You see more information about Frodo, and then I import Sam. The contact entry in the addressbook created for the import brings his phone number in too, which was part of the RDF but not explicitly shown in the document.
I hope to add support for other things like times, locations, and relationships. This way you can send somebody a document describing a meeting and they can import the time into their smart phone directly from the document... can we make retyping such information a vague memory like punch cards?