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What: Shares of BroadSoft (Nasdaq: BSFT) have plunged today by 23% at the low after the software and services company reported earnings with weak guidance.

So what: Revenue in the first quarter rose 29% to $38.3 million, with non-GAAP earnings per share of $0.29. Those figures bested consensus estimates for both the top and bottom lines, but the soft guidance overshadowed the earnings beat.

Now what: Second-quarter revenue is expected to be in the range of $36 million-$38 million, leading to non-GAAP earnings per share of $0.17-$0.23. The Street was looking for second-quarter earnings of $0.28. The full-year picture looks a little better, with fiscal 2012 sales expected to be between $158 million and $162 million with adjusted earnings of $1.22-$1.32 per share. CFO Jim Tholen warned that the environment is "a little more challenging now than it was a year ago, in terms of carrier buying patterns."

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Fool contributor Evan Niu holds no position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool has a disclosure policy. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.