"Die Nutzung sozialer Netzwerke im Internet durch Jugendliche“ [The Use of Social Networks in the Internet by Young People], lecture by U. Hasebrink at the conference of the Friedrich-Ebert-Stiftung "In Netzen gefangen?! Jugendliche in virtuellen communities“ [Caught in Nets?! Young People in Virtual Communities] in Berlin on 16 September 2009.