Excellent review of the Freebase project that includes a video of the Parralax Browser in action. Incredible stuff! Great video
Google is essentially a media company - as Tom Foremski succinctly points out here - logging your actions for Ad Word generation like a supermarket rewards card program while leveraging brute force search of the indexed web as you search for your keywords and phrases.
Wikipedia is essentially a single destination site, which means lots of laborious single issue searching.
The semantic web is a vision of information that is understandable by computers, so that they can perform more of the tedious work involved in finding, sharing and combining information on the web.