Each of these options has its advantages and disadvantages, and the correct path can be determined only by analyzing your own situation. Purchasing email software and installing it often requires heavy up-front expenses. Customizing the software and training your staff to maintain it can put pressure on many organizations. The advantage is that this option can create data-sharing opportunities with other departments or other aspects of your organization that may find uses for the list and the data it generates. The other key factor for installing software is security.
Many organizations have rules about customer or prospect data residing on third-party servers.
Purchasing and installing a solution to be run internally on your own servers eliminates this issue. Another option is to pick an ASP, which is considered the hottest thing in software. All of these service providers give you the same thing, which is providing you with access to software and its functionality over the web. Instead of installing the software and running it on your own servers, a third party takes care of that entire step for you. The advantage is that the up-front costs are usually very small.