On November 11, two United States Internet Service Providers (ISP) banned McColo firm’s access to the Web, after an investigation conducted by the Washington Post revealed that the hosting company was actually a haven for spam groups.

Since the ISPs pulled the plug on the firm, Ironport anti-spam company has informed that junk mail levels had gone down by 70%, adding though that spamming was still a threat to Internet users.

Spokesman for Ironport Jason Steer has stated that the decrease was only a temporary one, until spam groups could find other less supervised locations to host them, when junk mail would begin to flood people’s accounts yet again. Moreover, he reckoned that junk mail levels would rise again during the holiday season.

Washington Post newspaper kicked off their looking into the McColo firm four months ago and after they gathered enough data, they reported their conclusions to their Internet Service Providers Global Crossing and Hurricane Electric, which were the ones to take the firm offline.

The investigation’s findings suggested that McColo had been hosting gangs of spammers that ran botnets, a collection of software robots used to automatically send spams and malware, which according to provider of integrated messaging and web security services MessageLabs is behind 90% of spam.

The term spamming refers to the abuse of electronic messaging services in order to send unsolicited e-mails to a large number of people.

Although spammers don’t usually receive responses to the e-mails they send, research has showed that spamming still manages to turn a profit.