Abbreviations like “LOL” and “HDL” (for hab’ dich lieb, or “love ya”) and the Like button – all of them are things that Anna Metzler has seen for several hours a day recently. Metzler, a psychologist, is doing research on the behavior of teens and young people on the social network for her dissertation at Freie Universität Berlin under the working title You and Facebook, and that includes using Internet jargon and abbreviations like LOL (“laughing out loud”) and HDL.