Although the Internet is well into its second decade as a robust means of electronic communication, the availability of email addresses is still patchy at best -- although the email database helps to make up for the lack of a centralized "telephone book" for the web. The problems facing collectors of email addresses include the rapid rate at which emails are created and abandoned, and the concerns of email owners about privacy, spam, and unwanted communication should their email address become publicly available. However, given the need for accurate email directories, the email database is also a potential money-maker for anyone with the knowhow and persistence to create it.
An email database is a collection of email addresses for hundreds or thousands of people, most of whom have opted into the database in some way. For example, email websites such as Yahoo and Hotmail may collect members into a directory as part of the membership sign-up process, making an email database which is then searchable by other members. Other databases are not associated with an email account or other service, but simply exist as a partial directory of email addresses on the web.
There are many ways in which the owner or potential owner of an email database can encourage people to list their email addresses with their site. One way is to offer a 'change of address' service where people can list their old and new addresses, so that friends and associates can find them after they have gotten a new email account. This, of course, also creates a potentially searchable database of email addresses. If you are planning to create such a database, be certain to include plenty of privacy filters so that your clients aren't bombarded with spam by random bots around the world. Make it so that names and possibly locations must be entered prior to receiving information on a person's email address.
Another set of ways to get people to include their addresses in your email database is to offer them something in return. People love to receive stuff -- especially if they don't have to pay for it. Giving you their e-mail address has no monetary cost to them, so many will perceive it as being free. Of course, since your monetary resources are also limited, you don't want to give them something that is going to cost you very much, either.
Fortunately, if they are giving you their e-mail address, they are also giving you exactly the tool you need to reward them for their help in increasing the size and reach of your database. Newsletters (possibly written by freelance writers), contests, discussion forums, and useful articles that are only accessible after providing a valid email address to the database are among the possibilities for sweetening the opt-in process.
Creating an email database is a challenging process, not least because of the complex balance of trust, security, and accessibility that must be maintained, but there is plenty of demand for email finding services and plenty of room for expansion for the enterprising website creator.