The growth of online social networking, text messaging and cell phones is making traditional e-mail marketing efforts less effective, according to JupiterResearch.

A recent survey of more than 100,000 Internet users found up to 22 percent had reduced their e-mail use, replacing it with newer communications tools, the New York-based research firm reported this week.

The number of e-mail users who were prompted to make a purchase by an e-mail message was also down, falling to 44 percent from 51 percent last year, the survey found.

"Consumers' confidence in e-mail has become shaken by irrelevant communications and high message frequency, which are top drivers of subscribers' churn and channel skepticism," researcher David Daniels said in a statement.

Daniels said the rising volume of daily e-mail made it impossible for most consumers to pay attention to every message. As such, e-mail marketers need to be more direct and succinct with promotional messages, he said.