Google conducts tens of thousands of search experiments every year, and you never know which ones will actually become features of the greater Google experience, but the search engine is running a new one that's pretty interesting and shares some traits with actual features in other Google products, which could actually improve search results, and lend visibility to deserving content.
The test puts an "In-depth articles" section within the organic Google web results in a Universal Search-like fashion. It highlights (presumably) long form content relevant to your query. Tipped by Dr. Peter Meyers from Moz, Search Engine Land points out the test with a screen cap. Here's what the relevant portion of the page looks like:
As I mentioned, this shares some similarities with other existing Google features. For one, Google already highlights content as "in-depth" in Google News.
The icons Google shows for each publication match the icons they're showing in the latest version of the Gmail Android app. When there is a Google profile pic that Google can use to associate with the publication (or in Gmail's case, sender), it uses it. When there is not a Google profile pic, Google displays the first letter of the publication (or sender) in a box. It's kind of an odd way to to do it, but it shows some consistency between Google products, and I would not be surprised to start seeing this format pop up in other places throughout the Google universe.
As for the new "In-depth" articles test, the feature seems to keep in line with Google's mission to surface high quality content, and would complement the Panda algorithm update in that regard. The feature could reward orignal reporting and analysis - at least the kind that takes a great deal of time and effort on the part of the author. Granted, there is certainly plenty of original reporting that is not long-form or in-depth.
Either way, if this becomes an actual feature, this will give content providers more of an SEO reason to produce long articles.
In Google News, Google also has a "highly cited" label. It would be interesting if Google added a feature for that similar to the "in-depth articles" one.
It's interesting that Google would display this test on results for a query like "mexican restaurants," where users most likely wouldn't be looking to read in-depth articles in most cases.