International audienceThis article proposes an analysis of the different forms of structuration of online thematic communities. It additionally describes some typical trajectories that lead to specific structural positions while building up a reputation within these communities. It draws on two corpuses, one French and the other German, each containing some ten thousand websites and blogs, manually classified according to their main theme (technology, home, cooking, politics, etc.). We apply a model for characterizing sites according to incoming and outgoing links, within and outside of communities, and thus propose a map of the different structural positions. This map highlights the opposition between two ways of building up authority: the...