1. A computer program product for using user preferences to customize answer output comprising: a computer readable, tangible non-transitory storage device; and program instructions stored by the computer readable, tangible storage device, which, when executed by a processor, cause a computing platform to: extract, by a natural language processor, from a first question, one or more preferences for a first user; extract, by the natural language processor, from the first question, one or more sentiment levels for the first user; perform a semantic search on the first question; receive, from the semantic search, a first plurality of candidate answers to the first question; score, using the preferences and the sentiment levels extracted from the first question, each candidate answer to the first question; select one or more of the received candidate answers to the first question according to each corresponding score; output to the first user, via a user interface device, the selected one or more candidate answers to the first question, wherein the first user interface device comprises an output device selected from the group of a display, a printout, and a speaker; extract, by the natural language processor, from a second question, one or more preferences for the first user; extract, by the natural language processor, from the second question, one or more sentiment levels for the first user; accumulate the preferences extracted from the second question, the sentiment levels extracted from the second question, the preferences extracted from the first question, and the sentiment levels extracted from the first question, to form a set of accumulated preferences and sentiment levels; perform a second semantic search on the second question; receive from the second semantic search a plurality of candidate answers to the second question; score, using the set of accumulated preferences and sentiment levels, each candidate answer to the second question; select one or more of the received candidate answers to the second question for according to each corresponding score; output to the first user, via a user interface device, the selected one or more candidate answers to the second question, wherein the user interface device comprises an output device selected from the group of a display, a printout, and a speaker.