Various embodiments of the invention provide systems and methods for classifying physical documents that have been converted to digital documents. Specifically, some embodiments are configured to classify digital documents that belong to a document classification whose representative members that lack structure or have varying structure, either of which makes automatic classification of such documents using conventional methods difficult. For example, certain systems and methods according to the invention can be used to classify physical real estate documents that have been converted to digital real estate documents, especially those that lack a discernable document structure.