Hello, dear readers!

Because I found no better place, I ask this questions here. They are practical ones and have a philosophical side too, because they try to look behind the horizons of all the working time that spend users all over the world to tag, rate or comment files with KDE / Nepomuk. So here is the first question: Is the metadata (tags, ratings, comments) that I assign to files somehow connected to the options, I set up in system settings -> desktop search? (Are any of the limitations regarding folders to index / MIME types or file masks not to index valid for assigning metadata to files?)
The second one is the one with the filosofical twist (as Garfield would say): What are limitations for the life time of my tags, ratings & comments? (Example: I move all my text documents to a new machine, the freshly arrived family NAS. What about my tags, ratings, comments now, is all the time I spent to do the tagging, rating and commenting lost? (And even if I only copy the documents to the NAS - how to duplicate the assigned metadata to the new system to make it available for all authorized users?))
The idea behind my questions is one that goes behind the abilities of Nepomuk and the whole KDE by now, although, it's deeply bound with the idea of the semantic desktop as such (find information that is connected with other data via semantic relations). But to use all this stuff and make it work successfully some day, there should be basics first. One of this first steps (that sometimes lead to quantum leaps) for me is to store metadata persistent with a file (preferably without changing the original) beyond the frontiers of local accounts, file systems and even physical media and on the other hand leave it easy to handle, as all users are familiar with. And as long as that's still a vision (third question now:), are there any tools to milk or feed the Nepomuk database, that read or write all collected metadata from a database to human-and-machine-readable files (like XML) or vice versa?
Thanks for your time to read this. And any hint and answer of my questions is really appreciated.

Cheers
Aldicku

moved to Semantic Desktop

In terms of the storage of some of the metadata at least, such as tags and comments, this information is retained solely within the Nepomuk database - and is not stored in the files themselves. As such it will only be accessible to the user who created it - it will not be available to any other system or user.

I'm not sure if there are any tools to extract or import data into the Nepomuk database, however Nepomuk does offer a facility to perform a backup of it's internal database, although I doubt this is in a form which is usable by anything other than Nepomuk itself.

I found myself an answer for the first question: Is the metadata (tags, ratings, comments) that I assign to files somehow connected to the options, I set up in system settings -> desktop search? (Are any of the limitations regarding folders to index / MIME types or file masks not to index valid for assigning metadata to files?)
The answer is a superposition of both alternatives, and in german, we call it Jein. Yes, because unchecking the topmost box in General settings of Desktop Search switches off the ability of tagging, rating and commenting without removing any existent content of this types from the Nepomuk data. And no regarding to the indexed places, file and MIME types, it simply doesn't matter if the folder was scheduled for indexing or not, I'm free to make annotations, tag or rate any visible files, as long as Nepomuk and Virtuoso is running.

And even for the second question "What are limitations for the life-time of my tags, ratings & comments?" I was able to gather some knowledge now by the good old trial & error method. For that reason I know now: Each move of tagged data outside the physical machine, i.e. move it to a external media (or a mounted remote file system, destroys the assigned tags, ratings and comments. Each move inside our physical file system keeps this kind of metadata sticky to the file. Any copy action stripes any Nepomuk-specific metadata from a copy. So if you annotate a file in i.e. Dolphin or Gwenview and make a duplicate of it (even in the same folder) the duplicate is free of the made annotations. (I don't have any idea what is the intention of that but that's the state at the moment in KDE 4.11.2.)
So every tagged file, you'll send to an archive, you'll lose the metadata you assigned to it. (And even restoring it to the same place won't recover any of that information.) No way of preserving this and assign it to the file it belongs to out of the box by now.

That really is a sobering result in my opinion, because it means that we are forced into a more or less static file system of our user data (not allowed to remove any parts of it without loosing any kind of metadata) and renders working with comments, ratings & tags quite useless, even more than it was under Windows with ADS, which had no built-in capabilities to collect and harvesting this metadata on the other hand. For me the current state of Nepomuk looks half-baken, no genius plan reveals when you look at the facts of Nepomuk's semantic desktop so far, although there is a bright vision of how it should be like.
What lacks? At least a add-on to each linux file system that handels metadata native and let them stick to the files like NTFS does, so that no more assigned metadata gets lost just because of a damaged or switched off Virtuoso. Also ajustable signs of health or sickness of the database and its APIs Nepomuk, Akonadi & Virtuoso. Import & export of at least all user-entered metadata from / to configurable, human readable files. Methods and widgets that allow mediate users to work with semantics too, even without a bachelor degree.

Thanks to all who read this so far and maybe even wasted some thoughts about it
Aldicku