The service is free for anyone with fewer than 50,000 posts per month, and for companies with 15 employees of less. For professional sites or sites with larger volumes of posts, the service starts at $5 (£3) per month, per site.

The issue of abuse of blog and forums by malware hawkers is long established and the company's own research indicates that it's become a big enough issue to drown most unprotected sites with posting spam.

Defensio monitoring has also been integrated with the company's Web Security Gateway system.