Delivery and tracking of email campaigns is a complex task and one which could consume Yammayap full-time in its own right! Instead we work closely with Constant Contact (http://www.constantcontact.com). Their solution offers a very flexible platform on which to design and deliver email broadcasts plus it provides excellent analysis of delivered emails, opened emails, forwarded emails and clickthroughs to specific URLs. This is a truly robust, feature rich and mature solution - based upon a straightforward pricing mechanism which allows unlimited emails for a single monthly fee calculated according to the size of your database list.
Yammayap is well versed in integrating Constant Contact's signup forms and designing / implementing effective email stationery for repeated self-use by the customer.