There is buzz today about Metaweb decloaking and launching Freebase.com. Both Tim O'Reilly and The New York Times are covering it.
It's a bit of a tease, actually, since Freebase.com is in alpha release and you have to put your name on a list for an invitation code. (Like the early days of gmail). But if you do get in, you might be interested in the documentation I wrote for Metaweb: Developing Metaweb-Enabled Web Applications.
The sign-up for the invitation code is in the lower-right corner at Freebase.com
What is intended to be the difference between freebase and wikipedia?
Julian,
I'm not sure if the terms of my NDA have expired, so I don't want to try to explain how freebase compares to wikipedia. But I think that Tim O'Reilly addresses that in his article.
David