Farewell, Kin. We hardly knew ye. Microsoft (Nasdaq: MSFT) is killing its Kin social smartphone less than two months after it hit the market.

Alas, the Kin's flop isn't really a surprise. Did anyone remember the original springtime ad campaign, where we were asked to follow Rosa Salazar on her cross-country trek to visit her 824 "friends" through Facebook, Twitter, and MySpace? Creeeeepy.

More than just a Microsoft-powered smartphone, the eclectically shaped Kin aimed to be a social networking tool. The software did offer some compelling sharing features, but it fell into the same trap as Microsoft's own Zune -- or Barnes & Noble's (NYSE: BKS) Nook -- did when it comes to bar-raising sharing functionality.

In part, the Kin, Zune, and Nook are all duds because you need a large volume of fellow users in order to run into people that you want to share social media, music, and e-books with, respectively.

You can make the coolest Dixie cup in the planet, but if no one is at the other end of the string, it's just a pretty piece of nothing.

If you don't know any of the 1.7 million Apple (Nasdaq: AAPL) iPhone 4 owners, just wait a few weeks, and you'll find plenty of people to test out the FaceTime video chat functionality.

So it's not a shock to see the Kin fail to generate any real buzz. That said, it's still a surprise to see Microsoft kill it off so quickly. The Zune has been meandering in iPod's long shadow for years, yet no one's taking it off life support. Why kill the Kin? Its swift death sends an ominous message to Microsoft's wireless partners, especially as Mr. Softy prepares to throw more of its weight behind its new Windows Phone mobile platform, in hopes of gaining ground against Apple, Research In Motion (Nasdaq: RIMM), and Google's (Nasdaq: GOOG) Android.

Verizon Wireless -- a partnership between Verizon (NYSE: VZ) and Vodafone (NYSE: VOD) -- was aggressively marketing the Kin. What now?

Once again, Microsoft aimed its marketing campaign at jaded hipsters who know better. Once again, Microsoft is on the outside, looking in at another revolution that has moved on without it.

Why do you think the Kin failed? Share your thoughts in the comment box below.

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Longtime Fool contributor Rick Munarriz really does find himself surrounded by more and more Apple appliances these days, but he does not own shares in any of the stocks in this story. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.