We have a number of applications where we want to apply multiple tags
(keywords) to list items (including doc lib items). Then we want to filter
based on one or more tags. We have applications where a controlled
vocabulary of tags is appropriate and others where "folksonomy" (free
addition like del.icio.us) is appropriate.

OTB tools don't seem to support this. We can put keywords in a text field,
but there is not OOTB filter criterion on "contains", only exact matching.

How would you folks address this in MOSS?