It’s a brand-new way for Facebook to give you a view over the past years showing you the most popular statuses you shared in 2013, along with comments.
I’m still unable to understand the logic and algorithm behind it: it’s not sorted by popularity alone, most shared and liked images and statuses are not in top position, nor it’s sorted by date… some Facebook secret recipe we’ll never be aware of.
You can try it out for yourself by entering such an URL: https://www.facebook.com/yearinreview/[your Facebook username]
As you can see, an animated header tells you’re looking at the Year in Review page (and not your regular profile).
It would be actually cool to get the same feature (four images, slideshow, fading transition) instead of (or alternative to) the regular (static) profile image.