To export a domain from one geodatabase to another a ArcView user has to use two tools in the Toolbox: Domain to Table and Table to Domain. These tools could be combined to one convenient tool Copy Domain.
This idea has been merged with Domain Management Toolset.
With ArcGIS 8 and 9 I used Geodatabase Designer to exchange domains between geodatabases, but ESRI has ceased the development of this program. ArcGIS Diagrammer has the same functionality, but it is to no use to ArcView users because the license does not allow us to work with XML schemata.