The GAO report's authors looked at the privacy practices of 14 mobile companies, with 11 of the 14 being carriers, operating-system developers or app developers. Ten of the 11 disclosed that they used customers' location data, but many policies were "not clear," the report said.
Four of the companies described ways they used personal data, but did not say whether they consider location data to be personal data, the report said.
Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's e-mail address is email@example.com.