Content security vendor Websense has announced the acquisition of social media anti-spam firm Defensio.

Websense said that the acquisition will enable its ThreatSeeker Network technology to detect and remove spam posted as comments on Web 2.0 applications such as blogs, user forums and social networking sites.

Over 95 per cent of all posts on blogs, forums and other sites are unwanted content such as spam and malware, according to Websense research, while more than 70 per cent of all spam and unwanted content is hosted on legitimate sites that allow user-generated content.

Websense said that it will also improve Defensio's web services so that third-party Web 2.0 developers can embed Websense content classification technology into their applications.

"We have already integrated Defensio intelligence into the ThreatSeeker Network, giving existing customers broader protection from Web 2.0 security threats by making Websense products even more universal, accurate and effective, " said Websense chief technology officer Dan Hubbard.

"For example, Websense recently used Defensio-derived intelligence to detect that the popular my.barackobama.com presidential social networking web site was hosting links to malicious content within its user-generated blogs."

Websense plans to support and enhance the Defensio platform for personal and commercial users, and will continue to offer the comment spam filter at no charge for personal use and as a free six-month commercial trial for businesses.