http://alternativeto.net/software/tabbles/?platform=

http://tabbles.net/

Data Management, collaborative tagging The tabbles are special containers that you can use to categorize any kind of file and document as well as folders and bookmarks. Using Tabbles you can quickly categorize, find , sort and share your documents, in a totally new way

http://en.wikipedia.org/wiki/Fingerprint_%28computing%29

Metadata handling

Nepomuk, the technology behind metadata and semantic search in KDE applications, now provides a graphical interface to back up and restore data. Many performance and stability improvements have been made as well.