According to US-based net think-tank the Nielsen Norman Group, people can have highly emotional reactions to e-mail newsletters.

However firms wanting to create a relationship with customers through newsletters have an uphill struggle against spam, the survey said.

"Legitimate e-mail is at war with spam, and spam may be the ultimate winner," said Nielsen Norman Group's Jakob Nielsen.

"We saw in our study that fear of spam and other e-mail abuse can keep users from dealing rationally with newsletter subscriptions," he said.

Personal contact

People can feel a greater connection to commercial organisations that send them regular newsletters, which in turn means more loyalty, the research found.

A poorly presented newsletter will have a more damaging impact on the relationship than would a bad website

Jakob Nielsen, Nielsen Norman Group

"Newsletters feel personal because they arrive in your e-mail inbox, and you have an on-going relationship with them," said Mr Nielsen.

"In contrast websites are things you glance at when you need to find an answer to a specific question," he said.

It will be bad news for companies that have spent a fortune on a flashy website but great news for marketing executives searching for new ways to get in touch with the online community.

Simple things

The study observed a group of users subscribing and unsubscribing to newsletters and asked them to evaluate each one.

It emerged that surfers only like newsletters if they can simplify their lives. They did not like text-heavy messages and less than a quarter were read thoroughly.

Subscribing and unsubscribing also needed to be very simple in order to interest users.

Careful planning of what the e-mail should say and how it is laid out is also crucial.

"While the positive emotional aspect of newsletters helps create a bond between user and company, a poorly presented newsletter will have a more damaging impact on the relationship than would a bad website," said Mr Nielsen.