In some embodiments, a system may comprise a database and one or more servers. The database may, for example, store a plurality of content claims for previously evaluated data items, with each of the plurality of content claims being associated in the database with a corresponding stored digital fingerprint of a previously evaluated data item. The server(s) may, for example, be configured to receive a determined digital fingerprint of a data item from a client device on another network node, to submit a query to the database using the determined digital fingerprint as a primary key, and to transmit one or more content claims returned by the query to the client device. In some embodiments, the server(s) may be further configured to receive the content claim(s) and the digital fingerprint associated therewith from one or more computers on another network node, and to cause the received content claim(s) and digital fingerprint associated therewith to be stored in the database.