Soprano has been developed as a dependency for the Nepomuk-KDE (http://nepomuk.kde.org) project. As such, it is developed in the KDE subversion repository and most development issues were resolved through the proper KDE channels.
Now, however, it seems that interest in Soprano has also came up outside the KDE project. Thus, the bug tracker on SF has been activated and a new soprano-user mailing list has been created.