A just-released study by the Pew Internet & American Life Project reveals that although the volume of spam is growing in Americans' personal and workplace email accounts, email users are less bothered by it than they were before.

Less exposure to pornographic spam -- cited as the most offensive type of unsolicited email -- and an increased use of email filters combined with greater awareness of what constitutes spam contribute to their reactions.

The study's author points out the good and the bad of the situation. The good news: Spam has not become a significant deterrent to the use of email, as some observers speculated it might when unsolicited email first began flooding users' inboxes several years ago. But the bad news is it continues to degrade the integrity of email. Some 55 percent of email users say they have lost trust in email because of spam.

Simms Jenkins, founder and principal of BrightWave Marketing comments: "Legitimate marketers could feel the effect of this trend as consumers continue to 'tune out' other emails that they deem irrelevant or classify as spam, which they may define based on sender frequency or an overly promotional tone. In addition to declining response rates, this in turn can cause brand dilution and a decline in company trust, something most marketers don't necessarily associate with email marketing."

Jenkins advises that an email marketer's best chance for success is using email as a relationship tool and providing subscribers with meaningful, unique and relevant information and offers.

Full survey results available here.