Spammers now own email's dirty reputation

Nearly all of the internet-connected computers that send email are controlled by spammers, according to companies that track email reputations.

Less than one per cent of systems that send email can be deemed a good citizen of the internet, according to Return Path, a company that compiles email reputation data. Return Path collects data on 20 million IP addresses that send email, the company said on Tuesday.

George Bilbrey, general manager of delivery assurance products at Return Path, which specialises in helping companies get their email delivered to in-boxes, said: "The majority of email out there is spam. It is coming from compromised hosts."

Reputation-based filtering is emerging as a new technique to keep spam out of in-boxes. Senders are graded on their practices and assigned a reputation score based on several variables, such as complaint rates, volume of mail sent, and response to unsubscribe requests.

Companies such as Habeas and Return Path are stepping in with reputation services, hoping to make money by placing paying customers on "safe" lists and providing information about bad emailers to ISPs and sellers of email security products, such as IronPort.

Of the 20 million IP addresses that send email and are tracked by Return Path, only 0.9 per cent have earned a reputation score that will allow their emails to be delivered to Return Path clients, the company said. About 2.5 per cent encounter problems such as spam traps or having garnered too many complaints. But 96.7 per cent score so badly the sending computer is likely to be a hacked PC, the company said.

Spam makes up almost 75 per cent of all messages sent today, according to email security service Postini. A lot of spam is sent through hijacked computers, or so-called zombies. Yet, zombies aren't the only ones with trouble: up to 25 per cent of legitimate, commercial email gets blocked, according to Return Path.

The statistics Habeas reports are similar to Return Path's data. Habeas tracks 140 million IP addresses that send email. Habeas CEO Des Cahill said: "Over 99 per cent of those are evil."

Habeas and Return Path use the statistics to pitch their products, which they promise can improve spam filters and help commercial emailers, such as banks and online ticket-booking agencies, get their messages delivered to customers.

Joris Evers writes for CNET News.com