Darl is an Artificial Intelligence language and system for representing knowledge in Fuzzy Logic rules, implemented as a suite of REST interfaces in a SaaS framework.
On-line Tools exist to create and edit rule sets directly, derive them via natural language conversations or machine-learn them from your data.
Once you have a rule set you can create a questionnaire out of it for use in web pages, email or twitter exchanges, or just use it directly.
Free apps are provided so you can use Darl inside Microsoft Azure or the Microsoft Bot Framework, to integrate inference and conversation into your business processes.
Open-source usages of this site and the associated web services are free. Private and secure accounts can be set up for commercially sensitive applications.