Wanted to say I am having this exact problem right now. I ended up solving it using Campaign Monitor and zapier to get signups into Highrise CRM. I will look at using your system next time - any chance you've thought about making the data available in a structured way, such as csv/json either in the email or attached?

This is brilliant.

I wanted a solution like this for static websites, especially ones that I host on S3.

This is a great idea. Do you plan on keeping it free?