If you have a Mac or PC, open your browser and head over to a Wikipedia page, like this one on the Mona Lisa.

Hover over a link and you should see a brand new behavior. Instead of a tool tip (a tiny snippet of text), you should see a fairly substantial preview of the linked page. This is a huge improvement.

From Wikimedia:

This seemingly cosmetic change may seem far from revolutionary, but has been built through careful and vigorous A/B testing; scaling APIs to Wikipedia levels of traffic and a change to how we build our code (blog post to follow). Our testing shows that the feature makes it easier and more efficient for Wikipedia readers to interact with our content and get more context about a topic on Wikipedia.

And:

The goal of page previews was to decrease the cost of exploration for each blue link you come across, allowing readers to satisfy their curiosity or clarify a confusing or unknown topic without the burden of opening a new page and navigating back to the original.

More reading on this change: How we designed page previews for Wikipedia — and what could be done with them in the future.

A few stats from that last article:

• Nearly ~28 percent of Wikipedia’s traffic comes from clicking on internal blue links. a.k.a going down the rabbit hole
• Blue links account for ~230 million page views per month
• ~2 million links get hovered per minute across all Wikipedias

I love Wikipedia, I think this is a wonderful move. Note that if you don’t see the previews, check to see if you are logged in. If so, head over to Preferences > Appearance and click Enable in the Page Previews section.