Torben,
Thanks for your contribution. I'll check out the code as many public installs of OpenACS could use this type of feature.
Traditionally, changes that affect every page through changes in blank-master should be discussed with the OCT to get feedback and advice. The OCT is responsible for maintaining all core packages, and individual members will take on specific packages at various times. For example, I review all changes to acs-content-repository for historical reasons.
In this case, it might be possible to create the share-bar as an optional feature that can be used by any subsite package. There have been many changes with package type extension and template inheritance that might change the best way to implement this kind of feature.
