As Powerset begins to trawl the Web beyond Wikipedia, it needs to find a niche in which keyword searches are insufficient. One thing Powerset does have in its pocket is an enormous encyclopedia of synonyms. To show off the technology, Prevost asked me to type in, "What did Al Gore say?" The results include "Gore stated," "Gore argued," and even "a bill created and introduced by then Senator Al Gore." A similar Google search is a lot less coherent.
There are a bunch of potential uses for what I'll call "approximate search." I wrote a rather tortured paper in college about how Mark Twain is quoted in modern media. A Powerset-like news search would have been really helpful—it would have saved me from having to think up all the different phrases you could possibly use to invoke Twain, and then conduct an individual Nexis search for each one.
Perhaps this is the best that Powerset and other semantic search engines can hope for: We'll continue to Google for most things but use specialized search engines for the nooks and crannies where keyword search fails to reach. These niche sites are commonly called "vertical search engines," as they focus on one area in much more depth than a broad, "horizontal" search engine ever could. For a few examples, check out a people-search product called Spock or the travel-oriented Kayak.
For a Web startup, it's expensive to go vertical. Jay Bhatti, the co-founder of Spock, estimates that any site with aspirations to take on Google would require $30 million to $40 million to get off the ground, with a good chunk of that going to the thousands of servers needed to crawl the entire Web. Until Powerset can scrape that kind of money together—plus a few more million for the extra bandwidth to parse everything it retrieves—it'll have to be content to work at the margins. So long as Google directs its energies toward improving its universal search, this coexistence might even be productive—particularly if Powerset starts to crawl something more interesting than Wikipedia.