The valuation seems entirely justified to us, and one datapoint that goes to showing why is the fact that, according to this chart from Capstone Investments' Rory Maher, Pinterest already drives as much referral traffic as Twitter, despite being much younger and smaller.
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Pinterest already drives as much traffic as Twitter
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Wine marketplace Vinfolio raises $4.5 million in first round
75230
Facebook raises $1.5 billion, at a valuation of $50 billion
172350
Pure mobile content is overinvested--
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Warburg pincus raises $15bn
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API sees profits double
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Caplinked raises $0.53 million in angel funding round
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Yahoo!7 predicting strong growth
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Online group buying market reaches $155m
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Morgan Keegan maintains Market Perform on ADTRAN
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Young people more willing to pay for content than old
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TweetUp adds Topix
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GuruFocus valuation charts now support iPad/iPhone
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Jobsite launches jobs by Twitter
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Redrow encouraged by sales activity
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Study: 10% of Twitter users account for 90% of messages
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Social media marketing is long term