CrossRef Labs - worth a look!

If you work in the "information space", then it's nice to know that CrossRef have some developmental services, but there's one, (okay, two), in particular that I really like the look of:

1. Metadata Search complete with an OpenSearch plugin. This is not, of course a complete "search": "Instead, CrossRef Metadata Search is focused on allowing researchers to lookup citations using only terms that might appear in the bibliographic metadata of the item they are searching for."
2. an undocumented aspect which I discovered which is a more RESTful service providing the metadata for a given DOI. This is of the form: http://api.labs.crossref.org/{DOI}.xml