You can build a constituent's query to get the number of registered Altru users from your web forms

1. Click Analysis > Information Library > Add an Ad-hoc Query
2. Choose the Constituents Source View
3. Under the browse for fields in column click on the Online Information field
4. Drag Active from the middle column to the include records where section and set it equal to Yes
 User-added image
5. Click Preview results

The results screen will display the number of users at the top of the screen and the list will display the actual names