What does the 'Save URL data' Form setting actually do?
When this option is enabled, FormKeep will save additional information into the form data that is normally ignored.
For instance, wistia commonly captures the email of your viewers in the url before playing the video like this
Another example is the usual ad tracking information that is normally also on the url, for instance
Now, simply checking the 'Save URL data' option will instruct FormKeep to also save that information. It will appear in your form submissions just like any other data from your form.
FormKeep will be looking at three places for data:
Form POST data
Form POST action url
Source Page Url Parameters
The Form POST data is the normal <input> values from the form that are normally captured, these will take priority over any other value.
The Form POST action url can also have parameters on it, this is not terribly useful, because if you wanted to pass values to us and can edit the action url, you likely can also just add some hidden values to your form. But in some cases this might be an easier way to send us data.
The Source Page urls are just the parameters on the page that's hosting the form which points to FormKeep. You might have links to this page with utm_ arguements or you might have other values that your application is tracking via those parameters. Some of which could be useful to store in the form submission.
One other point, the Google AdWord tracking parameter gclid is a common parameter in urls, but the data itself is opaque to humans, so we're specifically stripping that value from the data before we save the submission.