The W3C recently started a working group to develop a provenance
information exchange format[1]. This working group is not try to
achieve exactly what SPDX does but their work seems likely to be
germane, and there might even be some overlap. The exact scope their
effort does not appear to be set yet but the incubator group, which
precede the working group, worked on topics like basic provenance,
provenance of changes, trust relationships and entailment (evidence
for provenance assertions). These are a lot of the same areas that we
have mentioned wanting to attack in future versions of SPDX.

It might be worth having some SPDX representation on the provenance
working group.

[1]: <http://www.w3.org/2011/prov/wiki/Main_Page>

Peter
openlogic.com