Google Photos, announcing the new feature on Google+:

Photos help us reminisce about the things we’ve done, bringing back events from one, two, or even ten years ago. Today, Google Photos is introducing a new opt-in feature where you can choose to privately rediscover your memories from the past. If you snapped photos on a hiking trip this time last year, chances are that Google Photos will let you know. And with a lifetime’s worth of photos and videos in one place, you’ll have lots of memories to look back on.

I’m still a little uncomfortable having all of my photos backed up on Google’s servers, but features like this make me happy that I decided to use the service.