Count activity per Day

Anonymous , Create a date column from datetime and then try this column

countx(filter(Table, [userId] = earlier([userId]) && [date] = earlier([date])),[userId])

date columns

Date = [datetime].date
or
Date = date(year([datetime]),month([datetime]),day([datetime]))

Anonymous ,

First create Calculated column to extract only Date part from Activity Datetime Column:

Date Column = FORMAT(Master[activity date/time],"DD/MMM/YYYY")

 

Then Create measure to count based on newly created Date Column:

Measure = CALCULATE(COUNT(Master[userId]),ALLEXCEPT(Master,Master[Date Column]))

 

Screen shot attached: