While extensive research has been conducted in topic segmentation for monologues (e.g., (Malioutov and Barzilay, 2006), (Choi et al., 2001)) and synchronous dialogs (e.g., (Galley et al., 2003), (Hsueh et al., 2006)), none has studied the problem of segmenting asynchronous multi-party conversations (e.g., email).
there is no reliable annotation scheme, no standard corpus, and no agreedupon metrics available.