• by Gavin O'Malley  @mp_gavin, February 25, 2009

If ever so slightly, consumers are allowing more company emails into their inboxes, according to a new study conducted by database marketing agency Merkle and research firm Harris Interactive/

The study, which aims to measure the attitudes and behaviors regarding permission-based email among U.S. consumers, found that the average number of company emails that consumer allow to clog their inboxes has increased from 9 to 10.

Why are existing subscribers most likely to opt-out of permission emails? The vast majority--75% and 73%, respectively--said the emails lacked relevance, and were sent too frequently.

Slightly more than half--53%--of consumers have added at least one company to their address books to ensure that emails land in their inboxes.

Slightly over half of respondents, meanwhile, said that they were less willing to sign up for email communications when compared to just a few years ago--showing that they are exercising caution.

"To grow their subscriber lists organically, marketers must continue to emphasize the value of their emails to consumers," said Lori Connolly, director of research and analytics in Merkle's Interactive Solutions Group.

Notably, an inverse relationship exists between the emails that are valued by consumers, such as transaction-related confirmations--64%--and account summaries--55%--and the quantities that they receive, such as news alerts--20%--and offers--18%.

For the report, Harris Interactive surveyed 2,505 U.S. adults age 18 and older who check and/or send email at least once a week.