This weekend I've attended the Nepomuk Coding Sprint. This has resulted in Koo adding semantinc information to files users extract from OpenERP. This includes files attached to records and printed PDFs too.
What it currently does is:
Tags: It adds the "OpenERP" tag to the file and also a tag with the name of the model, such as "Partner" or "Invoice" in user's language, of course.
If the document has a related partner or address and the e-mail is in user's addressbook, the document is marked as related to that contact. That means you'll be able to find the file when searching for files related to that contact. No matter if you try that in dolphin, Kontact or any other application that makes use of Nepomuk.
Tries to find a comment or note associated with the record (such as description in attachments or notes in partners) and attaches that as meta information to the file too.
Allows rating a record in OpenERP and the rating is exported to Nepomuk on user's computer.
I've created a video so that is a bit clearer:
All this is already available in Koo in 5.0 branch if you run it under KDE and install the new 'semantic' server's module.