Hello @gil100,
There isn’t a way to isolate which/how many contacts were specifically created by the users in your portal, however filtering contacts with the contact property “Hubspot Owner” might come close to what you are trying to accomplish. It won’t be perfect, because there are times when a contact might be added to a portal, but the Hubspot Owner is set to someone other than the person who added them. You can filter by Hubspot Owner by navigating to “Contacts” in the top navigation, “Add Filter” on the left hand side, type in Hubspot Owner, Click “Hubspot Owner”, select “is any of”, choose a user in your portal and click apply filter. This will display all of the contacts and provide a number of contacts owned by that user. You can also save this filter as a view, and repeat for all users in your portal so that you can easily access the views later on without having to manually add the filters everytime you want this information.
I hope this helps! I know it’s not a perfect workaround because it doesn’t provide the exact created by information, but it might come close to what you are trying to accomplish.
Brett