Update Google is now including search boxes in its search results.

If you search the world's most popular search engine and your search turns up a site that Google believes eminently searchable - including Amazon.com, The New York Times, and Wikipedia - you get a second search box that does nothing but search that site.

So, if you search on "Wikipedia," you not only get a link to Wikipedia. You also get an extra search box that lets you instantly search Wikipedia:

Google gives Wikipedia the VIWS treatment

Yesterday, Google blogged about this new feature, calling it "a tale of teleportation." When you key the name of a website into Google and Google links you to that site, Google thinks science fiction:

Have you ever forgotten the exact address of a site that you wanted to visit? Not a problem - just type the name of the site into the Google search box and hopefully it appears at the top of the search results page. We call this "teleporting."

We call it searching. But we'll indulge Google on this one:

One of the trends we noticed while studying teleporting was that there were lots of searchers who would type the name of a specific website as if they wanted to teleport, but would then immediately issue another more refined search within this site. For example, if someone is looking for official information about the Hubble Space Telescope on the NASA website, one might first search for [NASA] and then [NASA Hubble Telescope].

So, NASA gets its very own search box as well as Amazon, The New York Times, and Willypedia. What other sites get the VIWS treatment? How many sites get the VIWS treatment? Google won't say.

But it will say that these sites are chosen by super secret Google algorithms: "This feature will now occur when we detect a high probability that a user wants more refined search results within a specific site," read a statement tossed our way. "Like the rest of our snippets, the sites that display the site search box are chosen algorithmically based on metrics that measure how useful the search box is to users." ®

Update

As one Reg reader has pointed out, if you search on Yahoo!, Google does not provide a second search box. Obviously, the company believes that users aren't likely to be interested in doing additional searching on Yahoo! And the company is right.

Update 2

El Reg chip and server maven Ashlee Vance points out that Intel and Sun Microsystems get their own search boxes. Intel and Sun? But not Yahoo! or eBay? Either Google's CEO Eric Schmidt is pulling favors for people like Google board member/Intel CEO Paul Otellini and old chum Scott McNealy or Google's algorithms are rubbish.