Conjoint analysis is like AB tester, but more bigger more better: instead of testing one or two things, you can test potentially dozens of options. Where might you use something like this? Well, if you wanted to design an entire hotel chain completely from scratch, and to do it in a data-driven way. You'll never look at Courtyard by Marriott the same way again.
Relevant link:
main.file&fileID=466">https://marketing.wharton.upenn.edu/files/?whdmsaction=public:
main.file&fileID=466