But the novel worm spotted recently by Spamhaus routes junk via the mail servers of the net service firm that infected machines used to get online in the first place.

BBC: PC hard drive, Eyewire

"We've contained the routes through which incoming e-mail can pass, and that's how we were able to stop the proliferation of Melissa while we cleaned up all of the internal servers, " he says.

CNN: Stopping the next Melissa

The differentiation between offerings on leisure and business routes is driven by economics, David said via e-mail.

CNN: Continental cuts back on free food