Folks – you just HAVE to see the video embedded in this post about "Freebase Parallax"

http://blogs.zdnet.com/collaboration/?p=131

you'll never look at Google or Wikipedia in the same way again... its mind blowing.

That is interesting. So is it all open source and free software?

The navigation, although slick, seems much less powerful than that of relational database.

In the "Schools attended by the children of the US presidents" example, the interface makes it easy to get a list of the schools, but I don't see anywhere in the interface that you can delve into the list to find out, for example, which children went to each school.

In any case, the real value is not in this way of searching the data. The real value is that the underlying data sets are free (Creative Commons Attribution), so in a few years there will be hundreds of innovative ways of sorting, searching and manipulating this data.