Faced with increasingly clever assaults by e-mail marketers and other spammers, software companies are devising new tricks and technologies to combat the onslaught of unwanted online solicitations.

Anti-virus vendor Trend Micro and Qurb, a new company launched by the founders of software maker AvantGo, unveiled new ways this week to keep spam out of e-mail inboxes.

Qurb's software, priced at $25, screens e-mail by creating an approved-sender list. Trend Micro's application allows corporations to block unwanted e-mail before it gets into the network, for $4 to $30 per user depending on the number of licenses.

Spam -- unsolicited e-mail touting everything from Viagra to porn to get-rich-quick schemes -- touches everyone with an e-mail address. The amount of spam doubled in the past two years to an estimated 7.3 billion messages worldwide sent daily, said Mark Levitt, a research vice president at market research firm International Data Corporation.

[ Read more ]