By Tarmo Virki

(Reuters) - Some advertising networks have over the last year started to secretly collect app users' contacts or whereabouts, and could now have access to 80 million smartphones globally, U.S.-based mobile security firm LookOut said.

Over 80 million apps have been downloaded which carry aggressive ads and the problem was rising, LookOut said as it unveiled on Monday the first industry guidelines on how application developers and advertisers could avoid raising consumer angst over too aggressive ads, which could hit badly the $8 billion industry.

"Aggressive ad networks are much more prevalent than malicious applications. It's the most prevalent mobile privacy issue that exists," Kevin Mahaffey, LookOut's technology chief and co-founder, told Reuters in an interview.

He declined to name the most aggressive ad networks, hoping some of them would align practices to match the new guidelines which include publishing detailed privacy policy and a clear opportunity for consumers to avoid data collection.

Some more aggressive networks collect users email addresses or phone numbers without permission, while others install icons to home screens, track users whereabouts or push ads to notification bar.

"Most ad networks are not aggressive, but there are a few pushing the limits," Mahaffey said.

(Reporting By Tarmo Virki; Editing by Marguerita Choy)

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Browse our gallery of the most controversial apps ever banned from Apple's app store.
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  • Smuggle Truck: Operation Immigrant

    Boston-based developer Owlchemy Labs irked immigrant advocate groups with this iPhone game that allows users to drive a <a href="http://www.huffingtonpost.com/2011/04/28/smuggle-truck-operation-immigration-rejected-by-apple_n_854899.html" target="_hplink">truck full of immigrants</a> through the desert. According to the AP, "[Developer Alex] Schwartz said he wanted to bring attention to immigration issues." But Apple banned the app from the App Store.

  • Phantom Alert

    U.S. Senators Chuck Schumer, Frank Lautenberg, Tom Udall and Harry Reid pressured Apple, Google and RIM earlier this spring to remove smartphone apps that notify users of nearby police <a href="http://www.huffingtonpost.com/2011/03/23/senators-ask-apple-to-ban-dui-checkpoint-alert-apps_n_839300.html" target="_hplink">DUI checkpoints</a>. Apple and RIM have since <a href="http://www.huffingtonpost.com/2011/06/09/apple-dui-checkpoint-apps-ban_n_874532.html" target="_hplink">complied</a> with the Seantors' demands and cracked on so-called "DUI checkpoint" apps, but Google has yet to take action.

  • Exodus International

    Despite initially passing Apple's standards, the allegedly anti-gay messages promoted by the app "<a href="http://www.huffingtonpost.com/2011/03/23/apple-exodus-international-app_n_839448.html" target="_hplink">Exodus International</a>" outraged thousands of customers. The Exodus International ministry, from which the app takes its name, <a href="http://blog.exodusinternational.org/about/http://blog.exodusinternational.org/about/" target="_hplink">promotes</a> "freedom from homosexuality through the power of Jesus Christ." After more than 150,000 signatures were gathered for an online petition, Apple removed the app from the App Store entirely.

  • Playboy

    Hugh Hefner claimed in January that "Playboy" would soon come <a href="http://www.huffingtonpost.com/2011/01/21/playboy-ipad-app-blocked-_n_812489.html" target="_hplink">uncensored on the iPad</a>. Apple, however, remains firm on its nudity-free policy within the App Store and forced "Playboy" to resort to a low resolution web app instead.

  • Wikileaks

    The <a href="http://techcrunch.com/2010/12/20/apple-removes-wikileaks-app-from-app-store/" target="_hplink">unofficial WikiLeaks application</a> lasted only three days in the App Store before being banned by Apple.

  • 'The Importance Of Being Earnest'

    Apparently Apple's censors worried that Tom Bouden's graphic novel version of Oscar Wilde's <em><a href="http://www.huffingtonpost.com/2010/06/14/apple-censors-gay-kiss-in_n_611553.html" target="_hplink">The Importance of Being Earnest</a></em>, which portrays illustrations of nude or partially nude men embracing, would be too objectionable for too many users. Apple approved the app, but only with black boxes covering controversial frames. However, the App Store later reversed its decision and passed the app without the censor bars.

  • Big Brother Camera Security

    In 2010, Apple approved the <a href="http://www.huffingtonpost.com/2011/06/15/apple-bans-big-brother-camera-security-iphone-passcodes_n_877481.html" target="_hplink">Big Brother Camera Security app</a>, which lets users remotely photograph someone who is improperly trying to access their stolen or lost iPhone. In June 2010, however, the app was removed from the App Store following accusations that the developer was "surreptitiously harvesting user passwords."

  • ThirdIntifada

    Apple removed the app called "<a href="http://www.huffingtonpost.com/2011/06/23/apple-removes-anti-israel-thirdintifada-app_n_882857.html" target="_hplink">ThirdIntifada</a>" from the App Store, following complaints made by Israel's information minister, Yuli Edelstein and Jewish human rights group Simon Wiesenthal Center. The app was said to promote violence against Israel, according to claims.

  • Manhattan Declaration

    Apple initially approved so-called "anti-gay" app <a href="http://www.huffingtonpost.com/2010/11/24/apple-manhattan-declaration-app_n_788075.html" target="_hplink">Manhattan Declaration</a>, but the App Store later removed the program following a wave of complaints--and a petition--from outraged customers. The app asked users to sign a "declaration," which according to the app "speaks in defense of the sanctity of life, traditional marriage, and religious liberty."