The major app platforms have all agreed to ensure that developers provide comprehensive privacy policies for their apps before download.
The change is being driven by California's Online Privacy Protection Act, which California Attorney General Kamala Harris has decided now applies to mobile apps.
To stay the right side of the law, app providers will have to ensure that all apps have a clearly visible privacy policy and make sure all developers comply.
Apple, Google, Microsoft, RIM, Amazon and HP have all agreed to the changes.
There will be a review in six months time, so all the companies involved are likely to have made the changes by then.
Google is diving right in, confirming that it will be making the changes to the Android Market in a matter of weeks.
The long arm of the (Californian) law
Companies and developers who don't comply with the new act had better watch out – Attorney Harris has promised that California will hunt down (sue) any rule-breakers.
The new privacy rules come after US Congress quizzed Apple over the behaviour the Path app which was uploading users' address books without their consent.
Google has also recently been hauled up for privacy infringements for circumventing web browsers' security measures.