tip-off

私も一応Facebookのユーザーの一人ですが，個人情報の掲示についてはやはり気を付けなくてはいけませんね（専ら閲覧専門ですが。）。tip-offは「情報，内報，警告，〔…という〕手がかり，兆候」という意味の表現です（『ジーニアス英和辞典』第4版，大修館書店）。informationも「情報」を意味する一般的な語ではありますが，chat感覚，実際は重要な個人情報でも気軽に掲載していることから，ここではtip-offが用いられていると思われます。（GP）
Many Facebook users unaware of privacy risks: report
TechnologyMay. 05, 2012 - 06:46AM JST( 11 )
Many users of Facebook are unaware of the privacy risks, Consumer Reports saidAFP
WASHINGTON —
Many users of Facebook are unaware of the privacy risks from the massive social network site or fail to take adequate precautions, a report by Consumers Reports says.
The report found nearly 13 million U.S. Facebook users do not use, or are not aware of the site’s privacy controls.
An estimated 4.8 million Americans have posted about where they planned to go on a certain day—a potential tip-off to burglars, the report noted.
And it found that 4.7 million have “liked” a Facebook page about health conditions or treatments, details that insurers might use against them.
(Japan Today, 2012/05/05)
http://www.japantoday.com/category/technology/view/many-facebook-users-unaware-of-privacy-risks-report