It is crucial in many information systems to organize short text segments, such as keywords in documents and queries from users, into a well-formed topic hierarchy. In this paper, we address the problem of generating topic hierarchies for diverse text segments with a general and practical approach that uses the Web as an additional knowledge source. Unlike long documents, short text segments typically do not contain enough information to extract reliable features. This work investigates the possibilities of using highly ranked searchresult snippets to enrich the representation of text segments. A hierarchical clustering algorithm is then applied to create the hierarchical topic structure of text segments. Different from traditional clustering algorithms, which tend to produce cluster hierarchies with a very unnatural shape, the approach tries to produce a more natural and comprehensive hierarchy. Extensive experiments were conducted on different domains of text segments. The obtaine...