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What: Shares of LinkedIn (LNKD.DL) plunged today by as much as 14% after the company reported earnings with disappointing guidance.

So what: Revenue in the first quarter was $324.7 million, easily topping the Street's forecast of $317.1 million. The non-GAAP earnings per share of $0.45 was also well ahead of consensus estimates, which were calling for just $0.31 per share. The real cause for investor concern was conservative guidance.

Now what: Second-quarter outlook calls for revenue in the range of $342 million to $347 million, which is below consensus at $359.2 million. Adjusted EBITDA in the quarter should be $77 million to $79 million. Full-year sales are expected in the range of $1.43 billion to $1.46 billion, also short of expectations. LinkedIn grew its member base to 218 million.

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