What were you doing this day a year ago? Thanks to your obsessive use of Facebook, Twitter, Foursquare and/or Instagram, this information can now be mined in the blink of an eye. Sadly, the answer will probably be depressing.

The New York Times' Jenna Wortham signed up for a variety of digital nostalgia services, including PastPosts, MorningPics, and the horribly named "4squareand7yearsago" (get it?).

Each emails you a summary of what you did one year ago on a particular social network. They are fun to read about, but kind of depressing in practice. Odds are, your life has changed very little in the past year. Here's what the narcissism newsletters told Wortham about November 16, 2010: "I spent the day working from a local coffee shop. As the sun began to set, I picked up some takeout from my favorite eatery and spent the rest of the night writing in my living room." Ugh, the quintessential day in the life of a tech writer. We know the pain. How did Wortham spend today? Tech writing, apparently.

Social networks: Giving you a front row seat as the lives of you and your friends are slowly subsumed by social networks. Since 2002.

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