I am reposting a more modern announcement for this new feature.
This weeks (May 9th ) Rhino WIP now includes a new UI for 2 commands that were previously only accessible via the command line or through scripting. GetDocumentUserText and GetUserText.
These new interfaces can be seen in the following ways:
A document properties page
Rhino Options - Document Properties - Document Text.
A command that produces a floating or dockable tab panel
Command Name: DocumentText
An object properties page
Highlighting an object and visiting Properties - Attribute Text. Will display a panel to edit per object attribute user text.
Key / Values can be filtered by entering a filter parameter in the filter text box.
The Attribute Text UI context menu will also allow document object selections of matching criteria.