In an op-ed for The Washington Post, technology columnist Geoffrey Fowler writes that a study by fraud and compliance software company Pixalate found more than two-thirds of the most popular iPhone applications used by children share their personal information for advertising purposes, while 79% of popular Android apps do the same. He said tech companies need to act or laws are needed to impose responsibility. “We the users want children’s privacy to be protected online. But parents and teachers can’t be the only line of defense,” he said.