On this page, you'll find help for the batch-mode del.icio.us bookmark editor, Scripted Re-Mark. You can see some simple examples, get a handle on the Tag Tidy function and "touched tags", understand regular expressions, perform a mass delete or get some tips and tricks.
Revealicious is a set of graphic visualisations for your del.icio.us account that allow you to browse, search and select tags, as well as viewing posts matching them.