Google is testing a method to compare the set of search results it gives you after you enter a query. Google lets you select a number of search result snippets and compare them. Well, technically it is to compare different web pages...
Sergey Alakov spotted this and posted a screen shot of this on Twitter:
It says "quickly compare pages by making a group. To start, touch & hold a link."
I did some Googling to find this and I found this string in this Android chromium string - but I am not sure if this is a Chrome specific feature or a Google search specific feature.
I asked Sergey to send me more screen shots of the feature and it does seem Chrome based, not necessarily Google Search based.
Click on any of those images to enlarge them. It seems like a Chrome desktop feature now being tested on mobile.
Forum discussion at Twitter.