Is there any escape from the spam onslaught?

It is limiting the number of messages that can be sent in a 24-hour period to 100, down from 500 a day.

"This change is one way we are preventing spammers from using Hotmail as a vehicle to send the unwanted e-mails," said Lisa Gurry, lead MSN product manager.

Spam has been an exploding epidemic on the Internet, with about 30% of all e-mail flying around the net is thought to be junk mail.

Costly nuisance

The new limit on outgoing messages came into effect on 12 March and only affects users of the free Hotmail service.

MSN Extra Storage and MSN 8 subscribers are exempt.

SPAM FACTS 30% of e-mail is spam Spam will exceed normal e-mail by July 2003 Most annoying spams purport to carry free passwords to sex sites Sources: Surf Control and Messagelabs 2002's most annoying spam

Microsoft said it said the limit as a reasonable cap, explaining that it would affect less than 1% of its active subscriber base of 110 million.

The company also uses spam filtering software to try to block junk messages from crowding inboxes.

It also stops users from sending mail to more than 50 different addresses at a time and it maintains an internal "blocklist" of known spammers.

Other big e-mail service providers such as Yahoo and AOL have also got tough with spam, recognising it is a major nuisance for web users.

Experts estimate that spam costs businesses around the world about $9 billion a year to deal with and there seems to be no sign of an end to unsolicited mail.

Last year, one in 12 e-mails passing through MessageLabs' filter system was identified as spam.

The e-mail filtering company has warned of a dramatic rise in the amount of spam clogging inboxes, predicting the junk messages will exceed normal e-mails by around July.