1. A method of associating one or more comments with one or more primary electronic documents, the method comprising: identifying, at a comment association system, one or more key terms from at least a portion of the one or more primary electronic documents; identifying, at the comment association system, one or more comments associated with the identified key terms; wherein identifying the one or more comments comprises: determining a measure of the likelihood of a key term and a marker being found together in a comment; and determining whether the measure of the likelihood of a key term and a marker being found together exceeds a predetermined threshold and if so, identifying comments containing the marker; determining, at the comment association system, whether an identified comment is sufficiently related to the one or more primary electronic documents by calculating one or more relation score for that identified comment and comparing the one or more relation score to one or more threshold; and if the identified comment is sufficiently related to the one or more primary electronic documents, then associating the identified comment with the one or more primary electronic documents at the comment association system.