LinkedIn wasn't alone.

Fueled by successful Internet debuts, U.S. venture-capital backed initial public offerings fared well in the second quarter, with an above-average return of 17%, while private-equity-backed issuances held their own with an average return of 11%, said Renaissance Capital LLC in a report issued Thursday, June 30.

The momentum is likely to continue, as the U.S. IPO pipeline swelled during the quarter, with 93 companies bringing the total to 172.

Technology remained the best-performing sector, with professional networking company LinkedIn Corp. topping Renaissance's list with a 100% return in the first debut of a major U.S. social media company. But social media also accounted for the worst-performing IPOs of the quarter, FriendFinder Networks Inc. and Beijing-based Renren Inc.

Nevertheless, the Greenwich, Conn. research firm expects investor enthusiasm for the sector to continue. "With warm receptions of other category-leading Internet companies, such as Yandex, online radio service provider Pandora and vacation rental marketplace operator HomeAway, we expect positive momentum in the space to persist, benefitting IPO candidates Groupon, Zillow, Zynga, LivingSocial, Twitter and Facebook," the report said.

While the IPO market outside the U.S. enjoyed the second-most active quarter since 2007, performance was "anemic as macroeconomic concerns stemming from the debt crisis in Greece, tsunami in Japan and rising inflation in China roiled stock markets, diminishing investor risk appetite," the report said.

Asia Pacific was the worst-performing region, with an average return of -5%. Europe performed only slightly better, with an average return of -3%. Chinese IPOs may continue to be viewed with some skepticism on the part of investors concerned about fraud allegations and increased regulatory scrutiny, Renaissance predicts.

Overall, the firm has a positive outlook for global IPOs.

"With high-profile names such as Groupon, Zynga, old-line companies such as Dunkin' Brands and Toys 'R' Us, and global leaders such as Bankia, New China Life and Repsol Brasil all preparing to go public, the global IPO market is on track to see a resurgence in activity in the coming months," its report concludes.