I wanted to take Alteryx out for a drive to see what it could do and decided to look into the Tableau XML, in particular using Alteryx to dynamically update Tableau parameters. This is something I've worked on before (see Creating a Dynamic Parameter with a Tableau Data Blend) and last year at the Tableau Conference Bryan Brandow & Andy Kriebel demoed a solution that they'd built for Facebook with the same basic idea as my Alteryx one. The particular use case is one of the most requested ones for dynamic parameters, namely updating the parameter list as the data changes.