In AI, “special purpose” is usually referred to as “domain specific”. This of course was the promise of the IBM Watson APIs on Bluemix; however, IBM has withheld the key component, customizing the knowledgebase, to only premium, approved IBM Watson Ecosystem members. There are other engines available, experimental, open source, as well as quite a few high end, enterprise grade services within the CRM sector. Otherwise, I suggest perusing all of my answers under the Quora topic.
See also my quick and dirty webpage: