“Your personal privacy should not be the cost of using mobile apps, but all too often it is,” Ms. Harris said at the time.

But simple disclosure, in itself, is often insufficient.

The makers of Angry Birds, Rovio Entertainment of Finland, discloses its information collection practices in a 3,358-word policy posted on its Web site. But as with most application makers around the world, the terms of Rovio’s warnings are more of a disclaimer than a choice.

The company advises consumers who do not want their data collected or ads directed at them to visit the Web site of its analytics firm, Flurry, and to list their details on two industry-sponsored Web sites. But Rovio notes that some companies do not honor the voluntary lists.

As a last resort, Rovio cautions those who want to avoid data collection or ads simply to move on: “If you want to be certain that no behaviorally targeted advertisements are not displayed to you, please do not use or access the services.”

Despite multiple requests by phone and Internet over five days, Rovio did not respond to questions.

Policy practices like Rovio’s often do little to inform consumers. Most people simply click through privacy permissions without reading them, said Mr. Hong, the Carnegie Mellon professor. His institute is developing a software tool called App Scanner that aims to help consumers identify what types of information an application is collecting and for what likely purpose.

In Europe, lawmakers in Brussels are planning to bring Web businesses for the first time under stringent data protection rules and to give consumers new legal powers, the better to control the information that is being collected on them.

Proposed revisions to the European Union’s General Data Protection regulation now before the Civil Liberties, Justice and Home Affairs Committee of the European Parliament would require Web businesses to get explicit consent from consumers to collect data. A proposal would also give consumers the ability to choose what information an app can store on them without losing the ability to use the software.

But the drafting of the revisions, which are not expected until late 2013 at the earliest, has set off a concerted lobbying battle by global technology companies, most of which are based in the United States, to weaken the consent requirements, which could undermine the advertising-

financed business models that drive many free applications.