MyEperiment is a JISC funding social site for uploading and sharing workflows. I think I can learn from the model

System Ontology

[img[filestore/uploads/systems/class_hierarchy.png | http://mit.edu]]
One of the things that makes this site interesting is their data model. The ontology is explained here but I didn't want to lose it so I made a local copy of their graphic. Here is a link to the ontology specification.