EN: This looks very promising - Freebase combines the Web 2.0 (community based data generation/maintenance) and semantic web (using meta data for making information better "understandable" for machines) philosophy in one application. It's the first child of the company Metaweb (nomen est omen) and will be Creative Commons licensed (nice!). Tim O'Really wrote a helpful introduction (that was bashed because of an "outdated view" about the semantic web). bbgm mentioned briefly the potential for science. At the moment you have to be invited to sign in, however you should keep an eye on it.
Update: Freebase has now a blog called Freebasics.