  We address the problem of cross-referencing text fragments with Wikipedia
pages, in a way that synonymy and polysemy issues are resolved accurately and
efficiently. We take inspiration from a recent flow of work [Cucerzan 2007,
Mihalcea and Csomai 2007, Milne and Witten 2008, Chakrabarti et al 2009], and
extend their scenario from the annotation of long documents to the annotation
of short texts, such as snippets of search-engine results, tweets, news, blogs,
etc.. These short and poorly composed texts pose new challenges in terms of
efficiency and effectiveness of the annotation process, that we address by
designing and engineering TAGME, the first system that performs an accurate and
on-the-fly annotation of these short textual fragments. A large set of
experiments shows that TAGME outperforms state-of-the-art algorithms when they
are adapted to work on short texts and it results fast and competitive on long
texts.
