He has made a few contributions, including vivace-graph (a very young graph database / RDF store), cffi-wordnet (an interface to Wordnet 3.0), cl-skip-list (a lock-free skip list implementation), the cl-neo4j client library, a patch to mel-base, debugging concurrency issues with Ian Eslick in Elephant / BDB and adding (not yet accepted) client certificate support to Drakma. He is also the maintainer of Ian Eslick's langutils NLP library. See my repositories on github for more: https://github.com/kraison.
His email address is firstname.lastname@example.org
His website is http://chatsubo.net/