Salesforce Interaction Studio is the more common of the two in our index: it runs on 208 websites against 17 for Viafoura. Counts come from real scans, not vendor claims.
Salesforce Interaction Studio (formerly Evergage) is a cloud-based software that allows users to collect, analyze, and respond to user behavior on their websites and web applications in real-time.
Viafoura is an audience engagement and social monetisation platform.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.