Send-Safe, written and run by Russian Ruslan Ibragimov, is the most popular vehicle used by spammers to distribute unsolicited marketing emails.
The news has been greeted enthusiastically by anti-spam campaigners who had been lobbying MCI to stop hosting the Send-Safe website for some 18 months.
"MCI kicked Send-Safe off its network three days ago but did it rather quietly," said Steve Linford, director or anti-spam lobbyists Spamhaus. "And Send-Safe has since been kicked off three other networks."
According to Linford the MCI snub could be the beginning of the end for Send-Safe.
"It was on MCI for 18 months before being kicked off. Before that they were kicked off four Chinese networks, which is quite an achievement," he said. "No other network in the western world will host Send-Safe because of the illegality of its operations. It's based on hijacking hundreds and thousands of private, virus-infected computers."
The Send-Safe program uses zombie networks of computers infected with viruses such as SoBig and Mydoom, that, without the user's knowledge, send spam to potentially millions of customers worldwide.
MCI has come under a lot of pressure from the anti-spam community to improve its spam problem. Last month SC reported MCI makes $5million a year knowingly hosting spam networks.
Despite its reputation MCI has been the subject of a recent takeover bidding war. In Febraury SC reported MCI had accepted a $6.7 billion bid for the company by telecom leviathan Verizon.
Since the acceptance Qwest, which originally bid $7 billion and was rejected, has renewed its attempts to acquire MCI at the eleventh hour. The anti-spam fraternity has voiced a preference towards Qwest, which it feels has a better anti-spam policy.
In January MCI itself was spending at the sales, forking out some $105 million for security firm Netsec.