Unfortunately, a lot of the e-mails are barely worth reading -- or at least that's what the people who handle them believe. Interest groups generate most of the incoming e-mails and a numbing percentage of those are form letters. Half of the aides surveyed are convinced that constituents aren't even aware that they've sent such identical-form communications, and another 25 percent of staffers question whether those communications are legitimate at all.

There are companies that erect Web sites for interest groups, others that help to target e-mails to congressional aides and offices, and still others that do both. And every one of them is working diligently to make their e-mails look and feel as authentic as possible. Some of the leaders in the field are GetActive Software Inc., Democracy Data & Communications LLC, Kintera Inc., Convio Inc., Vocus Inc., Soft Edge Inc., e-Advocates, and Capitol Advantage LLC which helped to fund the survey.

Many legislators try to discourage mass mailings by regularly altering the e-mail templates that they keep on their official Web sites. But the e-mail generators manage to stay a step ahead of them. The companies that route e-mails to Congress constantly monitor bounced-back messages as a way to locate the switcheroos and then quickly change their own procedures to ensure that the e-mails find their mark.