I would approach it like this:
If you have a 'thank you' or 'confirmation' landing page that shows after submission, you can use a web activity report and add filtering criteria in the Smart List with the specific landing page URL and time constraint. This should work whether you use Marketo landing pages or your own. On the subscription tab within the report, you can set it up to email you (or anyone else) the report daily.
I hope this helps!
Kara