1. A method of information retrieval comprising: (a) receiving from a user, data identifying a stored reference corpus; (b) retrieving the identified reference corpus from storage; (c) generating initial values of respective weights corresponding to a plurality of analysis algorithms by processing the retrieved reference corpus in accordance with a predetermined algorithm; (d) retrieving from storage another text document as a candidate document; (e) performing respective comparisons between the candidate document and the reference corpus in accordance with each of said analysis algorithms and producing respective comparison results; (f) generating corresponding weighted comparison results by multiplying each said comparison result by its respective weight; (g) summing the weighted comparison results to produce a dissimilarity measure that is indicative of the degree of dissimilarity between the retrieved reference corpus and the retrieved candidate document; and (h) storing the candidate document in a retained text store if said sum is indicative of a degree of dissimilarity less than a predetermined degree of dissimilarity.