Abstract: Methods of computing answer results to user-submitted queries, using a plug-in executor, a user database, a plug-in database, content recognizers, answer generators and a controller. Controller submits content recognizer specifications and sets of answer generator specifications to the plug-in executor, combines content recognition results, combines answer generator answer results, determines the subset of answer generators to execute using an answer generator set determinator, looks up the specifications for each answer generator in the subset of answer generators, and responds to the client program with a list of answer results.