According to Socrata's "Publisher Guide":
The Publisher API allows you to programatically:
Add, update, and delete records within a Socrata dataset
Maintain dataset metadata and privacy settings
But I can't see anywhere in the API docs that explains how to do this. It's all about creating, updating or removing individual rows - nothing to do with dataset metadata.
For instance - how do you add a tag to an existing dataset, using the API?