According to Google, hundreds of publishers are already using Google AMP, and the company says that AMP was devised for browsing the web on mobile devices. The average loads times for sites with pages built for AMP load on average four times faster, and use ten times less data than equivalent non-AMP pages.
Looking at the list of publishers already using it, there are quite a few, and you can see the a list of the sites from the amproject.org site.
Look out for the AMP logo next to a site in a mobile SERPs.
This is what it should look like. AMP in mobile search