Some users of the new social media service Google+ were inadvertently spammed with email notifications this weekend following a technical malfunction on the site. The error occurred during an 80-minute period when Google+, currently in beta, ran out of disk space on a system that keeps track of notifications, Vic Gundotra, a Google senior vice president of engineering, wrote in a Saturday post. “We didn't expect to hit these high thresholds so quickly, but we should have,” Gundotra said.