Google searchers can now quickly see a preview of webpages returned as a result of a query, without having to click through to see if the page is likely to give them the answer they are seeking.

"Instant previews" are snapshots of webpages stored on Google's servers that pop up on the right side of your screen. They can be launched by clicking on a magnifying glass that shows up to the right of a search-result link.

The addition comes just a month after Google debuted Instant results, where searchers on broadband connections get results in their browsers as they type, making the Enter button nearly obsolete. Unlike Google Instant, preview is not on by default for all searches, and only turns on once you click the magnifying glass on the page. Then, when you hover over any search result, you see a custom-generated preview of the target page that shows you exactly where the relevant snippet is in the page (see image below right), which can be helpful if your answer is toward the bottom of a long page.

The new feature will begin rolling out globally starting at 6 a.m. Eastern Tuesday, and should be available to all Google users in a day or two. The initial rollout will not include mobile searches, but Google is considering how to extend the features to smartphone users.

The previews are yet another indication that the fight over search dominance is now more about the user interface, than about who has the best 10 results on a page. Yahoo and Bing are both trying to differentiate themselves from Google, which retains nearly 70 percent of the U.S. search market.

Ben Gomes, a distinguished engineer who's been with Google for 11 years, says the new preview has proven to be useful in early testing, making users about 5 percent happier with their search results.

"This is part of making search more interactive and fun and fluid," Gomes said in a Monday briefing. "What we want to do is give users a hint of what a result page looks like and show them the keywords in the context of that webpage."

That part – the highlighting of where the result is on the page is the technical magic behind the new feature, according to Gomes

"We know where every word on the web lives," he said.

When the relevant result appears at the bottom of the page – such as in the Red Spider nebula picture search in image at the top of this post, Google's preview shows a broken line across the preview to indicate missing portions of the page. That way if a user does want to go to that page, they will know that their answer is at the bottom, not the top and not discard the result because they didn't immediately see a match.

The preview function does not extend to Google ads, even though every Google ad ends up at a webpage. Google has thought about the option, but isn't including it in the initial launch, according to Gomes.

What's interesting about the new feature is that Google normally crawls the web with a little spider which is more interested in how machines view the web than how humans do – it wants to record all the text, grab the metadata in pictures, and ferret out links. So to build a visual representation, Google has to do something more than spidering.

"There's a huge amount of computation involved in rendering the entire web," Gomes said. "We have to remember where all this stuff is, mimic what your browser would do, render a page and do a snapshot, and remember and identify the relevant portion of the page where your text is and break the snapshot apart and do that in less than 1/10th of a second."

Still, despite those efforts, some content, including some in Flash, can't be turned into a preview just yet.

Unlike Google Instant, which shuts off on slow web connections, Instant Previews is available to those on thin connections and could be more beneficial to those users than to those using fat pipes, since the question of which page to click and allow to load is far more crucial on dial-up than on a fiber connection.

Follow us for disruptive tech news: Ryan Singel and Epicenter on Twitter.

See Also: