1. A computer-implemented method for providing robust topic identification in social indexes, comprising: maintaining electronically-stored articles and one or more indexes comprising topics that each relate to one or more of the articles; selecting a random sampling and a selective sampling of the articles; for each topic, identifying characteristic words comprised in the articles in each of the random sampling and the selective sampling; determining frequencies of occurrence of the characteristic words in each of the random sampling and the selective sampling; identifying a ratio of the frequencies of occurrence for the characteristic words comprised in the random sampling and the selective sampling; and for each topic, building a coarse-grained topic model comprising the characteristic words comprised in the articles relating to the topic and scores assigned to those characteristic words.