Just head over to http://www.googleplusdaily.com/ on your smartphone to see the new slider. It loads in the background, so it may not appear immediately. If you're signed into Google+ in your mobile browser, you'll see specific recommendations from your circles (assuming they've +1'ed anything on GPD), otherwise you'll see a collection of "Popular Posts."
If you don't have an Android or iOS device to try it out on, you can actually still give it a try by changing your user agent in Chrome Developer Tools. There's more information on how to do this in the Developer Docs.
What do you think of the new mobile recommendations? Let us know in the comments!