Tracker is a search engine and that allows the user to find their
data as fast as possible. Users can search for their files and
search for content in their files too.  

Tracker is a semantic data storage for desktop and mobile devices.
Tracker uses W3C standards for RDF ontologies using Nepomuk with
SPARQL to query and update the data.

Tracker is a central repository of user information, that provides
two big benefits for the desktop; shared data between applications
and information which is relational to other information (for
example: mixing contacts with files, locations, activities and
etc.).