The professional social media group LinkedIn reported better-than-expected results Thursday, giving some relief to a sector battered by disappointments from Facebook and others. LinkedIn reported a profit of $2.8 million on revenues of $228 million in the second quarter. The earnings amounted to 16 cents a share excluding special items, in line with most forecasts. But revenues were well ahead of expectations of $215 million, and grew 89 percent from a year ago. Its stock price jumped more than five percent in after-hours trade. \"LinkedIn had a strong second quarter with all of our key operating and financial metrics showing solid performance,\" said chief executive Jeff Weiner. \"Our ongoing investment in product innovation drove healthy engagement as measured by unique visiting members and member page views, and our three revenue streams all experienced significant growth.\" LinkedIn\'s stock price has more than doubled since being introduced a year ago at $45, and was at $98.25 in after-hours trade. That contrasts with social media firms like Facebook, Zynga and Groupon, which have struggled since their public offerings. The California company launched in 2003 and made its stock market debut in May of last year to raise the money to fuel expansion. LinkedIn claims more than 175 million members worldwide, including executives from every Fortune 500 company, and describes itself as the world\'s largest professional network on the Internet.