Version: 3.5.7 (using KDE KDE 3.5.8) Installed from: Ubuntu Packages I think that it would be wise to implement Digikam's tags feature as KAddressbook's Categories feature. There would be a sidebar on which users could click to see only contacts in that category, and contacts could be dragged into categories easily. Also, this would help unify the KDE UI between apps.
The development of the old KAddressBook will be discontinued for KDE 4.4. Since the new application has the same name, but a completly new code base we close all bug reports against the old version and ask the submitters to resend there reports against the new product.