Just as an experiment, a friend of mine subscribed to ten different opt-in e-mail marketing lists to see which ones were the most effective. Many websites and online businesses have resorted to sending promotional materials to people who have subscribed to them in an effort to boost their sales or traffic.

Opt-in email marketing sends newsletters, catalogs updates and many more promotional materials to website visitors who have agreed to be updated whether monthly, weekly or semiannually....

Lists play an important role in any business that is using direct marketing. Lists not only provide the contacts of your customers and prospects, but sometimes also store valuable demographic and behavioral characteristics of these customers. Firms and individuals constantly need to revisit their lists in order to cater to additions, deletions, and changes.

List building is an ongoing process. Firms cannot make effective use of lists until and unless they are constantly upgraded....