The popular open source spam-filtering software, SpamAssassin, will have deadlier aim thanks to an add-on tool that is being offered free of charge to small businesses and individuals by MailChannels.

The tool - called Traffic Control 3 - is an email traffic-shaping package that slows down the transmission of spam into corporate email systems. MailChannels officials say Traffic Control 3 will reduce spam volumes by 50 percent to 75 percent for SpamAssassin users.

"Our technology is a software package that slows down spam from suspicious sources like spam bots,' said Ken Simpson, CEO of MailChannels. "Our research shows that 90 percent of spammers will give up before delivering spam if the data rate of the connection is slowed down.'

With less spam entering their networks, companies will need fewer mail servers to process or store email for their end users.

MailChannels has sold Traffic Control 3 to enterprise customers such as Pacific Gas & Electric, Cornell University and Wyeth for two years. Now MailChannels is offering a low-end version of its software to small businesses and individuals that use SpamAssassin.

Traffic Control 3 for SpamAssassin is available from today.

"Email traffic shaping is a technique used by many of the world's largest email receivers,' Simpson said. "We're trying to make this technology available to everyone.' More than 150,000 websites used SpamAssassin to filter their email traffic, Simpson said.

"SpamAssassin supports hundreds of millions of users. But SpamAssassin is limited because it is just a content filter,' he added.

Simpson said that MailChannels was giving the open source community access to its Traffic Control 3 software to spread the word of how well the software works and to get feedback from users.

"We know our stuff works, but the only way we have to show that was to put it out there. When you feed the open source community, the investment comes back and pays dividends,' he said.