Properties of blogging networks are derived from a model where bloggers devote attention to others, produce content for others, and exchange attention with content within their network of relations. The predictions from the model are tested with a novel dataset from LiveJournal, a major blogging community. The activity of a blogger is found to be related to the size of, and level of aggregate reciprocation within that blogger's relational network. Bloggers who do not adhere to reciprocity norms are found to have less readers than their activity might otherwise have predicted.