The _Final Report_ of the PCC ISBD and MARC Task Group (September 2011) has been posted online. 78 pages. PDF.
"The MARC21 community needs to transition to an environment where nearly all records created omit ISBD punctuation.
As an initial step in such a transition, the Program for Cooperative Cataloging called for the establishment of a task group to further investigate these issues. The PCC ISBD and MARC Task Group was established in March 2011 and was charged with the following: investigate the omission of ISBD punctuation from the cataloging process in favor of having cataloging interfaces generate punctuation needed for display; perform a field-by-field analysis of MARC to identify instances of embedded ISBD punctuation; and, identify the use of any non-ISBD punctuation present in fields."
The report is really well-done. Robert Bremer, OCLC, chaired the group.