In the presentation below, that Tim Berners Lee gave last February at the TED conference, the creator of the Web talks about what needs to come next: linked data. This is Berners-Lee’s explanation of the semantic web.

The internet used to only connect servers to eacher other. I remember how in the very late ’80s I logged onto a Unix machine at some US University to get some material from that machine using command line entries.
Berners-Lee thought it frustrating that you would find documents and files in all kinds of formats for which you might not have the right software to read it. Out of that frustration came the Web. It didn’t look all that great initially (see pic below), but it meant you could open a document from any machine, and have it link to other documents. The Web connects documents.

Early version of the CERN website.

Now he proposes to link data to eachother, much like we now link documents, and used to link servers to eachother. As the next step in the evolution of the internet.
How he imagines that you can see in the video. It needs loads of raw data however. Data that follows three rules: it is available in open formats, it has an URI, and it links to other data. Hence his call to arms: Raw Data Now!
Given the work I currently do on opening up public service information (PSI) in the Netherlands, I can only subscribe to that call. In his presentation Berners-Lee talks a bit more about what is important about opening up government data.