A fifth of the world's websites and mobile telephone applications provide no information on how, or if, they protect users' personal data, a French watchdog said Tuesday.
In collaboration with 19 other countries, France's national data protection agency Cnil in May conducted an audit of more than 2,000 of the world's most popular websites and apps to evaluate how they inform users of their data collection practices.
"More than 20 percent of the websites and mobile applications audited supply no information to their visitors in regard to their policies on data protection even though these sites or applications collect personal information. For mobile applications alone, this number even reached 50 percent," it said in a statement.
In cases when such policies are not communicated, users "do not have the means to control their data", Cnil said, adding that even when such policies are available, they are often too general or too focused on specific technical aspects such as cookies.
Internet services routinely install small bits of software, called "cookies", on users' computers to store identifying information and to track Internet behaviour.
All the authorities involved in the audit complained that essential information was often withheld, such as the purpose of the data collection or whether the information would be passed on to a third party.
They also pointed to the practice of "drowning" their policies on data protection in their general conditions statements.
In France, where Cnil said it had audited 250 websites, it found "99 percent of them collect data of private character".
Explore further: Industry, advocates finalize mobile app guidelines (Update)