Data extracted from the Web often come with uncertainty: they may contain contradictions or result from inherently uncertain processes such as data integration or automatic information extraction. In this habilitation thesis, I present probabilistic XML data models, how they can be used to represent Web data, and the complexity of the different data management operations on these models. I give an exhaustive survey of the state-of-the-art in this field, insisting on my own contributions. I conclude with a summary of my research plans.
