The BrightTALK Connector for Salesforce automatically sets a default Lead Source for leads created by the Channels you connect. That default value is:
"BrightTALK Channel - [ID of the Channel you Connected]"
If you wish to change this value, you can do this in the "Setup" area of your Salesforce instance:
1. Under "Build" select "Customize"
2. Then select "Leads"
3. Below Leads, Select "Fields"
4. Find the field called "Lead Source" and click on it (note: click directly on the field name, not "edit" or "replace")
5. In the picklist options, find the value(s) for your Connected BrightTALK Channels and click "edit" next to the ones you wish to change
6. Change the "Label" to whatever you want it to be and click Save. Note: do not change the "API Name" value, otherwise the Connector will not be able to update this field.
Note: You'll need to make this change for each BrightTALK Channel you connect.