In using XML in real-world application work and designing future infrastructure that is highly scalable and efficient while making use of XML, I have come to the conclusion that I need a standard way to deal with an XML analogue that is binary. There are a multitude of performance problems that this solves, not only in parsing and exporting, but processing of related data inside applications. My design has highly efficient Java processing in mind, but is not specific to any particular language.
Compression is a secondary, but associated issue.
A list for W3C XML Developers.