The Source column on the Users Data Report represents "Where" a user was registered or created from.
A self registration URL might look something like this:
http://www.brainshark.com/mswisher/register/1?581128
The template ID would appear in the source column of the Users Data report as 581128
Other values may appear and are noted below:
0 = is a manually created user from Admin
1 = is user created through the self reg. process
101 = is a user created through webservices, most likely through API (Salesforce CRM Connector, etc.)
102 = is from bulk upload process
105 = is specifically from SSO auto-create function
106 = User was auto created (Salesforce user sync, auto-create through Highspot, Salesforce, etc.)
