McAfee is about to enter the Web site security scanning market. The company announced plans to acquire ScanAlert, a company that certifies sites as safe if they can pass baseline vulnerability audits.

After a preliminary audit ScanAlert then periodically rescans the sites the ensure ongoing security compliance. Sites that pass ScanAlert's test can then display a "Hacker Safe" logo on their Web pages to let potential customers know that they at least meet ScanSafe's security requirements. To date the company has amassed over 75,000 customers.

McAfee said they'll pay or approximately $51 million in cash up front for the company and as much as additional $24 million if ScanAlert meets performance targets. ScanAlert will become part of McAfee's Web Security Group and the company intends to integrate ScanAlert services into it's SiteAdvisor Web rating system.

McAfee's other recent acquisitions include endpoint security solution provider SafeBoot, along with Citadel Security Software for its security policy compliance and vulnerability remediation, and Onigma, a company whose solutions help protect confidential data.

Microsoft recently entered into a marketing agreement with ScanAlert where Microsoft will offer a 20 percent discount to all of its adCenter customers.