In the days before Facebook was a social network with 600 million people, it used to be a nice place to post funny college photos of my roommate’s epic walks of shame or to invite a group of friends to a private party in New York City.

Facebook’s growth has sparked a slew of startups committed to providing users with targeted content sharing, and one in particular has caught our attention: The Fridge, a former Y-Combinator now New York City based startup, which is simply, “a really cool social network that makes it super easy to share your stuff with only the right people.”

Austin Chang, The Fridge’s Co-Founder, started the company one year ago after spending years working and teaching in the design world and working as an engineer in the first dot-com boom. Like an actual fridge, The Fridge is a place to post things for others to see, and to “keep your friends fresher.” Online, it acts like a social scrapbook, a place where users can create separate groups for friends, family, work, etc. Groups have an infinite shelf life, but once they are deleted they are gone forever.

The format of The Fridge is like a better organized chain email; if users aren’t a part of the discussion, their inbox isn’t inundated with crazy reply-alls. But the service does make it easy to update Fridge discussions via email if the user so chooses.

Screen shot 2011 03 02 at 10.36.54 AM 520x336 Forget Facebook and use The Fridge to plan your spring break

It’s a souped up FriendFeed or a private Facebook, in which friends can share multimedia posts and have conversations without the rest of the world commenting or being unnecessarily pinged. If someone is not a part of a group that you are a part of, they can’t access it. Group members can comment and like posts Facebook style as well as share individual posts with friends, groups, and on Facebook and Twitter, but mind you, outsiders will only be able to see select posts, not the entire thread of group page. One of the best features of the site, which has been redone twice since last September, is its “See All Photos” feature that simply displays all photos ever posted into a group.

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Since launch last August, Chang has seen 30,000 registered users create 20,000 groups focused on group vacations, community groups like sororities and fraternities, event planning and small-medium sized conferences. For conferences, the message board lets everyone meet each other before hand, then during the conference it acts like a repository, and afterwards organizers have one place to look at all of the conversations. He’s also seen it used in classrooms. Professors can share things with an entire class that they find on the web. Think of it like what Google Buzz never was, minus the realtime element.

Once you’ve joined more than a few groups, the “Shared Groups” feature shows you which contacts you share group connections with. This information is creating a very interesting cluster-social graph, “a fractal network of data,” if you will.

“The friend request isn’t how we relate people to each other anymore,” explains Chang. “Our relations are based on specific interests, groups and shared connections with other people.”

Screen shot 2011 03 02 at 3.57.46 PM 220x155 Forget Facebook and use The Fridge to plan your spring breakThe Fridge will be moving (slightly) away from its privacy and permissions ethos and focusing more on targeted contented with its upcoming Public Groups feature and events platform. Chang wants the Fridge to be the simplest and easiest way to share whatever you want. Also in the near future, the company will be releasing an iPhone app that Chang says will be like “if Path and FriendFeed decided to have a baby.”

With $800K in funding, the 5 person team is now focusing on pushing its product for spring break, having just announced a partnership with SWAT marketing for college kids heading to Lake Havasu, AZ. Together Fridge and SWAT are incentivizing college kids to join and meet other spring break partiers by giving away 10 trips for helping to spread the word. Check it out here and brace for nudity.