LinkedIn stock plummets more than 40 percent on weak outlook - CNET

LinkedIn's efforts to get professionals excited about its social network are not paying off as fast as some expected, especially investors.

LinkedIn announced Thursday that its fourth-quarter eaings and revenue had topped analysts' estimates. But the company's stock closed down 40 percent on trading Friday after it issued weaker-than-expected guidance. It was the second time in the past nine months the Mountain View, Califoia-based company's stock tanked on eaings news.

LinkedIn's grim prediction comes as the 12-year-old social network retools to attract new users beyond the 400 million it currently boasts. The social network, which helps users find jobs or just connect with others, is free to use but charges for features like advanced search and messaging strangers.

To build up its user base, LinkedIn has been expanding into new markets, including China, and adding new lines of business such as tools for advertising and marketing. To help its members leaing the right professional skills, LinkedIn said in April it had reached an agreement to buy Lynda.com, an online training site, for $1.5 billion.

LinkedIn is also trying to improve the functionality of some of its products to increase user engagement. In December, the company unveiled a dramatic revamp of its mobile app, which had been often criticized for being cluttered and difficult to navigate. Improving users' experience on the go is key as more than half of LinkedIn's traffic comes from people checking in on a mobile phone or tablet.