I've been using Heyday off and on for the past several months while in beta. It's been available for a while in a few countries (New Zealand or Canada, I think).
It's a personal journal with a heavy Timehop influence. It's most similar competitor is betaworks-backed Memoire (https://itunes.apple.com/us/app/...) which launched a few months ago.
What I love about the product is its use of nostalgia (I have a fun blog post in the works on this topic). When I visited my hometown a while ago, I received a push notification that read something like:
"You took a picture in Eugene, OR 1 year ago"
It knew I was in a different location, traveling from SF and it smartly re-engaged me with curiosity.
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