If you saw my earlier post about Wolfram Alpha, then you know that semantic search has been on my mind recently. To define it very broadly, a semantic search engine is one that understands human language as it is actually used. Current generation search engines operate by looking for keywords - we've all essentially trained ourselves to ask questions in a way that search engines understand. The challenge with this is that sometimes we're looking for something a bit too fuzzy for keyword-based search.

A good example of this is image searching. Suppose you were looking for a screencap from the scene in The Godfather where Don Corleone collapses in his tomato garden. Google Image Search is tremendously powerful, but it's keyword-based, so searching for this on GIS would entail a search string like "godfather collapse" and then trawling through the results until you find what you're looking for. An ideal semantic search engine could just be asked "Where can I find a screencap from the scene in The Godfather where Don Corleone collapses in his tomato garden?", and it would know precisely what you want. There's a lot of words in that query that are useless to a keyword search engine but that are essential for a human (or a semantic engine) to understand what you're after.

Stephen Wolfram made a post on his blog last week that sent hearts in the geekier corners of the Internet a-flutter. If Steve Jobs is the prototypical rock star geek, known the world over for his genius and one-dimensional wardrobe, then Mr. Wolfram is the influential indie rock act, influential in all the right places if not quite a household name. Wolfram's post unveiled his latest project: a search engine called Wolfram Alpha.

Within a couple of days, news of Wolfram's announcement started to spill over into the mainstream media. "British scientist developing 'Google killer' search engine" exclaimed the Telegraph. Fox News reported that Wolfram Alpha was positioned to "challenge Google". A ZDNet blogger asked if Wolfram Alpha was just "lots of hype".