email server and system

background our social networking site sends 40,000 email notifications to members per day (we have about 3 million members in total). when a member's photo, blog, or club receives comment, we send the email. in our current system, much of the email gets blocked as spam. the members want to be notified when people leave comments on their pages, and if members change their mind the bottom of email has a link to opt-out of the notifications. we do not want to make members tell their email system email from us not spam (members are passive, not active). your job: choose a virtual server that is not on isp spam block list, setup the send email system and a basic usage reporting html page for admin. each day i will ftp file to the server with sender, receiver, content information. what is the biggest challenge in this project? the coder here things only 10% chance this project can be done with success. your proposal will need to convince me there is more than a 10% chance this amount of email (with html links inside) can be sent to our registered members each day without us ending up on a spam blocked list.