It is best to experience this cool application yourself, so, I will just extract some excerpts from their own words below.
"del.icio.us direc.tor (del.icio.us direc.tor)":http://johnvey.com/features/deliciousdirector/ is a web-based rich UI for "del.icio.us (del.icio.us)":http://del.icio.us/. It leverages the XML and XSL services of modern browsers to deliver a responsive interface for managing user accounts with a large number of records.
*The main features are*
* In-browser handling of del.icio.us bookmarks (tested up to 12,000 records)
* Find-as-you-type searching of all your bookmarks, with basic search operators
* Sort by description, tags, or timestamp
* Ad-hoc tag browser