Simple script requires users to fill out a form and confirm their email address before a download can proceed. (with an opt-in box) When they follow the link sent to them in email, file is downloaded, at the same time, form data is sent to web site owner. If they opt in, their address is added to a list. It also provides an "opt-out" feature which enables them to remove their email address from the list. No database required and everything can be customized. An ideal way to collect marketing data or sales leads from your users before they are permitted to download files, product demos, etc..