1. A computer-implemented system for providing multi-core topic indexing in electronically-stored social indexes, comprising: a storage device comprising a corpus of articles each comprised of online textual materials; and a social indexing system, comprising: a finite state pattern for a topic filtering the articles as candidate articles, which are potentially on-topic; similarity-based representations for on-topic and off-topic core meanings of the topic; and a finite state modeler determining an aggregate score for each of the candidate articles using the similarity-based representations to indicate whether the candidate article is sufficiently on-topic; and a display presenting the candidate articles ordered by their aggregate scores.