bigtable/gfs master failure

"I can't use xs:all to represent (i) content models that can have elements appear more than once (e.g. multiple enclosures on an RSS item) and more importantly (ii) to specify that an unlimited amount of elements from any namespace can show up in any order in my content model"

"I think the UBL code model approach is very instructive, because it absolutely springs out of pragmatic organizational issues: you want to validate and model with a schema language, yet code lists change fast and may be out of the control of the people making the rest of the schema"