**3. Facebook**

Facebook was created in February 2004 by Mark Zuckerberg at Harvard University. The network was initially limited to students and later became a global phenomenon, accessible by anyone with an e-mail address. Facebook has become one of the seven most popular sites in the United States, with users around the world [6].

Facebook is also one of the most popular social networks in in Israel. According to a ComScore survey, penetration of Facebook among Internet users aged 15 and over is 89.8%. This is the second highest penetration rate in the world, after the Philippines. Israel is leading in duration of use, reaching about 10.5 h a month per user (Comscore.com).
