Qualtrics is the more common of the two in our index: it runs on 338 websites against 6 for Riddle. Counts come from real scans of each site's home page, not vendor claims, and cover the sites in TechLookup's index rather than the whole web.
Qualtrics is an cloud-based platform for creating and distributing web-based surveys.
Riddle is a platform enabling creation of lists, polls, and quizzes.
Within the surveys sites we have indexed, Qualtrics holds 32% and Riddle 0.6%.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.