See also PDTB Publications. PDTB is a shallow discourse representation, as opposed to RST-DT. According to Perret 2016 “the PDTB does not provide full discourse structures for texts,” but the RST-DT does.

PDTB sense hierarchy from Prasad 2014. There are three levels - most systems do level 2 senses but not the finer-grained level 3 senses.
Disentangling interleaved conversation threads (for example in multiparty dialogs).