This is a web-based Twitter Application.
When someone goes to the website, the url will be something like: [login to view URL]$member
where $member is the referring member's username. The website name should be configurable in a config file.
The visitor is presented with "the pitch" to follow on Twitter the members displayed on the page. The members that gets displayed on the page follows a specific algorithm based on their membership level. This should be easily "pluggable", so that the members displayed to be followed can be easily changed to use other algorithms.
This can be seen on this mock-up page: [login to view URL]
If the visitor is already a member in Twitter, the visitor enters in his/her Twitter username and password. The application then uses the Twitter API authenticate and to submit the follow requests on the visitor's behalf.
The visitor is now a member and can refer the site.
The new member is offered the ability to upgrade their membership to a monthly subscription. Their membership level will determine how often their profile gets displayed on the page for new visitors to follow them.
That's the basics of the "front-end".
There'll be a back-office part that shows stats on how many followers they have added using the system, and the ability to upgrade even more.
Here is the mock-up for the back-end: [login to view URL]
Payment system is Paypal or Credit Card and perhaps others..
Also, tie into an affiliate program and payout a two-tier affiliate bonus.