This paper discusses the pedagogical and technological aspects of assessing wiki-based collaborative learning activities. The first part of the paper presents a general framework of collaborative learning assessment. The framework is based on four aspects of assessment, characterized by four questions: who, what, how and by whom. The second part of the paper concentrates on the analysis of the applicability of the assessment framework in wikis. A systematic analysis of MediaWiki's reports is conducted in order to discuss the requisite information required for a well-balanced and effective assessment process. Finally, a few suggestions are raised for further improvements of the wiki's reports.