At last, Google has finally gained a page preview feature. Called “Instant Previews,” this is a way for you to see what’s on a page that’s listed in Google’s search results without having to leave Google.

The new feature seems promising, another way to save time in the searching process, because there’s less need for people to “pogostick” with their search results.

Pogosticking is when someone clicks from a search listing to a page, then clicks back if unsatisfied to select another result and so on. With the new Instant Previews, they may be better able to immediately spot the most promising pages among those listed.

Up Close With Instant Previews

In the new feature, which was spotted being tested last month, a small magnifying glass appears next to each listing:

Click on that magnifying glass, and a preview of the page that’s listed will appear to the right side of the search results:

Once you’ve enabled Instant Preview mode, you can also use your arrow key to move down through the other results. As you select one, it will be highlighted with a blue background. The preview will change to show the highlighted page:

More Than Just A Thumbnail

Previews that show a small “thumbnail” image of a page are nothing new. They’ve been employed by various search engines over the years. Ask.com, for example, launched its Binoculars service way back in 2004, through the feature appears to have been dropped as part of Ask’s recent makeover into a Q&A search engine. Google even began offering thumbnail previews last year, through its search options feature.

Bing tried a new twist on previews when it rolled out Quick Previews as part of its launch in 2009. By placing your mouse to the right of any listing, you get a longer textual summary of information displayed from the page itself, as with this example below:

Google’s system seeks to marry the two: an image of the page as well as extracting text. Rather than a small thumbnail image, it shows a much larger picture of what the page looks like. The larger image, and one that’s not in a standard square shape, especially helped with people finding the previews useful in testing, Google told me. In addition, the previews highlight the relevant text on the page — similar to Bing — but within the context of the image.

Callouts & Tears

Within the images, relevant text to your search is highlighted through “callouts” that make it easy to read:

Pages can have more than one callout:

Pages might also have have what Google call “tears,” where a page might appear to have been “torn” to show you the overall context of the page but also show you parts relevant to your search. Below, an example of a tear is shown between the two green bars:

Instant Previews & Ads

The images previews cover up Google’s ads, when they appear. Is this a problem for advertisers? Google says largely no.

The company told me that most people scan the search results page quickly. If they’re interested in the unpaid “editorial” results, they’ll tend to stay looking at them rather than going back and forth to the ads. In other words, previews aren’t blocking ads because if someone decides they want to focus on editorial results, they’re already ignoring the ads.

Ads, by the way, will also get an Instant Preview feature in the future, Google told me. There’s no set timeline for this, however.

Site Owners: You Can Block Previews

Don’t like the idea of Google making previews of your pages? As with Bing’s previews, you can also opt-out of Google’s. To do so, just make use of the nosnippets meta tag. Meta Robots Tag 101: Blocking Spiders, Cached Pages & More explains more about this.

Also, be aware that the descriptions shown for your pages in the results may be different than the callouts on the pages. Sometimes they match; sometimes they don’t. Different algorithms are at work.

Nice Addition

Google suggests that Instant Previews will make it easier to spot if a page contains a table, chart or picture you might be after, and says those using it will be 5% happier with their results. I agree. It should be a useful feature for many searchers in these or other cases. There have been plenty of times when a short preview would have given me a better idea if a site might be worthwhile to visit or not. And, if you don’t like it, well, don’t click on the magnifying glass and you won’t see it.

The preview begin rolling out today worldwide and should be in place by tomorrow for everyone. If you don’t see them yet, visit this special page at Google about Instant Previews and then click on the “Try It Now” link. Or, just click here to go directly to a special version of Google that will enable it.

To learn more about Google Instant Previews, also see Google’s blog post about it. For related coverage of this story across the web, see here on Techmeme.