How to perform a common operation on all contacts from a dynamic distribution list?
1 way is to export them in CSV, modify in CSV and upload. But, if I want to remove/add a category/keyword to all contacts, I believe this wouldn't work.
If there's no way to do it via CME, I would go with creating an application using Tridion.AudienceManagement.API.
Using 2013 SP1