The Fourth International Workshop on Uncovering Plagiarism, Authorship, and Social Software Misuse (PAN 10) was held in conjunction with the 2010 Conference on Multilingual and Multimodal Information Access Evaluation (CLEF-10) in Padua, Italy. The workshop was organized as a competition covering two tasks: plagiarism detection and Wikipedia vandalism detection. This report gives a short overview of the plagiarism detection task. Detailed analyses of both tasks have been published as CLEF Notebook Papers [3, 6], which can be downloaded at www.webis.de/publications.