When people ask me why I love Foursquare so much, I point to the service 4squareand7yearsago, which sends a daily email with the subject line: “Where you were a year ago on December 19, 2010. ”

The walk down memory lane is my favorite email of the day. I look forward to it every morning when I wake up even more so than MW’s Word of the Day or an email from my boss saying I’ve been paid. In October, the mad API geniuses–BennyJonathanSean and Rachel— released And7YearsAgram, its new Instagram-from-a-year-ago service that perfectly complements the Foursquare hack.

And this just in: Starting tomorrow, the email will be even more awesome. The team behind the two API hacks are now a full blown email memory service called Timehop. The ultimate daily nostalgia kick now includes your tweets, Twitter photos and your Facebook posts from every day, a year ago.

Timehop’s new integrations with Facebook and Twitter are sure to pull in a massive user base. It’s new design is quite friendly too.

Timehop is a brilliant service. After all, what’s the sense in documenting our lives on social networks if we never see that information again? Timehop’s email is a web logger’s dream come true.

So, what were you doing 1 year ago today? Sign up below.

➤ Timehop