A 27 year-old man from Seattle described as "one of the top 10 spammers in the world" has been arrested for alleged illegal spamming by US federal authorities.

Robert Alan Soloway was arrested on 30 May after a federal grand jury indicted him on 35 charges including mail fraud, wire fraud, email fraud, identity theft and money laundering. 

"He is one of the top 10 spammers in the world," said Tim Cranton, senior director of Microsoft's Internet Safety Enforcement Programme. "He is a huge problem for our customers. This is a very good day."

US authorities have said that email users can expect a drop in spam volumes following the arrest.

Through his company, Newport Internet Marketing, Soloway is accused of conducting spamming activities from late 2003 through to early this year.

Soloway used networks of compromised computers to send tens of millions of emails urging people to advertise their products through his company, authorities said.

According to the indictment, Soloway advertised a mass email service that sent messages to an opt-in list of addresses, but did not actually get permission from the people on the list.

It is believed that he often used forged source addresses and domains which resulted in some legitimate owners of the email address or domains being blamed for the spam and blacklisted by ISPs.

"Soloway has been a long-term nuisance on the internet in terms of the spam he sent and the people he duped to use his spam service," said anti-spam organisation Spamhaus.org. 

Soloway has pleaded not guilty to all charges. Prosecutors are seeking fines of over $772,000, the amount he allegedly obtained from his activities. If convicted on all charges, Soloway could face decades in prison.