Salesforce Interaction Studio is the more common of the two in our index: it runs on 171 websites against 75 for Sirdata. 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.
Sirdata is a self-service, third party data-collecting platform that specialises in the collection of behavioural data, predictive targeting and selling of audience segments.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.