'There are two ways of doing natural language processing: statistical or semantic,' D'Aloisio explains. A semantic system attempts to figure out the actual meaning of a text and translate it succinctly. A statistical system-the type D'Aloisio used for Summly-doesn't bother with that; it keeps phrases and sentences intact and figures out how to pick a few that best encapsulate the entire work. 'It ranks and classifies each sentence, or phrase, as a candidate for inclusion in the summary. It's very mathematical. It looks at frequencies and distributions, but not at what the words mean.'