According to Cloudmark Inc. CEO Karl Jacob, the San Francisco-based vendor will let corporate users of rival technologies test its Cloudmark Immunity software. And if they like Immunity better than what they already use, they can keep the software and won’t have to pay anything for it “until they stop paying for their current antispam product,” Jacob says.

He argues that IT managers rushed in tools to dam the flood of spam and that many companies are now dissatisfied with the results — either spam keeps coming, or the false-positive rates are too high.

Although most antispam products offer plug-ins for Outlook, few integrate with Lotus Notes. For Cloudmark, that’s due to end in next year’s first quarter, when the company plans to release an upgrade with built-in links to Notes mail clients.