Pinterest shares surged after the company topped Wall Street's fourth-quarter estimates and showed robust user growth from a year ago.

Pinterest Inc. posted strong holiday-quarter revenue and gave an upbeat forecast for sales in the current period, a sign that its advertising business continues to grow despite increased competition from much larger rivals in the social networking space.

Pinterest's adjusted earnings per share came in a bit light for the fourth quarter, but it's tough to find much else to be disappointed about. Monetization looks rather strong, especially in the crucial international markets,