Something I knew about but hadn't thought through until Kirrily Robert pointed it out to me yesterday at the Vancouver Freebase meetup is the importance of the 'as_of_time' parameter in freebase. This allows developers to access views of freebase data at any point in time. The important consequence of this is that it makes it easy to create authoritative versions of data in freebase. This means that if, for example, the gene ontology were loaded into freebase on a particular day by a particular trusted authority, users of freebase could access versions of the GO topics exactly as they appeared at that moment. This answers the common worry from biologists about trust and authority. The 'oh no, I wouldn't use anything that could be edited by just anyone' phenomenon goes away and the best of both worlds becomes a possibility. With an open app like freebase you get the wikipedian potential for rapid, parallel, collaborative knowledge formation. With this kind of versioning, it should be possible to create trusted, authoritative versions at any point in time.