1. A method performed by one or more computing devices for generating a self-updating naturally-reading narrative product summary including assertions about a selected product, the method comprising: evaluating, by at least one of the one or more computing devices, an existing narrative product summary including: reconciling the existing narrative product summary into an existing attribute associated with the selected product, and resolving forms in the existing narrative product summary into an existing assertion model; determining, by at least one of the one or more computing devices, at least one new attribute associated with the selected product; retrieving, by at least one of the one or more computing devices, assertion models defining forms in which an assertion can be manifested to describe the selected product, and to recommend an alternative product in a natural manner; receiving, by at least one of the one or more computing devices, a plurality of bids from manufacturers that indicate an amount of compensation each manufacturer is willing to pay to have at least one of the manufacturer's products be recommended as the alternative product; selecting, by at least one of the one or more computing devices, the alternative product based on the plurality of bids; and generating, by at least one of the one or more computing devices, an updated naturally reading narrative by combining the at least one new attribute and the selected alternative product with the retrieved assertion models such that the generated narrative includes a recommendation of the selected alternative product.