We are looking for a system to automatically capture leads and send out email auto responses.
Additionally, It is important to know the percentage of people that see a modal style box (div layer) lead capture form, or other type, in comparison to the number of people that close the form (if an overlay) or that actually complete the lead capture form. The system would need to have administrative account access, would need to be differentiable based on the pages where it's deployed, and would need to be able to manage campaigns from an administrative system.
Integration with mail systems would obviously also be a requirement including ability to opt-out of auto-responder email chains, etc. The server architecture would be standard LAMP configuration with PHP/MySQL database storage and using a PHP based mailing application.
The developer can customize other open source applications as necessary to complete this project as well.