Dr. Pete Meyers from Moz reports that the Mozcast feature graph is indeed correct in showing that featured snippets are now showing up almost 17% more often, 16.6% as Pete put it. He said it now shows up for 7.1% of the queries that Mozcast tracks.
Here is the graph:
Which queries? Here are some examples of new queries showing the featured snippets:
What does this mean to you? Either more or less traffic for your search results.
Of course, with the 4 ads and now this, it might be concerning for many.
Forum discussion at Twitter.
Update: It seems to have gone back to normal: