You can add specific tags to your Lead Capture Form. When someone fills in the form, those tags are added to that contact within 17hats.
In this example, every time someone fills in this form, the contact will then have the tag "Facebook" added. This way they can see which contacts came from which form, easily. And this will allow them to see which Lead Capture Forms have more traffic.
KeyWord Search: Lead, Tags, Lead Capture Form