Freebase has now opened its doors to anyone, at least for those who just want to browse and search. Looks like you’ll have to wait a while longer if you’re wanting to contribue. I’m still really interested in what Freebase brings to the party; how it compares and is different to Wikipedia – but most of all what such an open API can do for those of us mashing up data from across the web. When I get time (in about 2028 at this rate..) I’ll have a long hard look at their API and try a few ideas…
Meanwhile, there’s some lovely mashups already built – see for example CineSpin which is not only elegant and rather beautiful to look at but also extremely content rich, and (gasp) useful, too. There are more examples here.