Website security software company Websense has acquired Defensio, a comment spam blocker used by blogs. Terms of the deal were not disclosed.

Defensio competes with Akismet, the spam blocker that comes with Wordpress, and Mollom. One of Defensio’s features is that it can sort blocked comments by spamminess and also offers an API for use on Websites other than blogs.

Websense will incorporate Defensio into its ThreatSeeker Network, where it will help detect comment spam on blogs, forums, and social networks. Websense also plans on extending Defensio so that it works on broadly distributed Web applications.

The company recently used Defensio technology to detect malicious hackers on BarackObama.com. Moreover, Websense claims to have research showing that:

. . . more than 95 percent of all Web posts on blogs, forums and other sites are unwanted content such as spam and malicious content. Additionally, more than 70 percent of all Web spam and unwanted content is hosted on legitimate sites that allow user-generated content.

That sounds inflated to me, but comment spam definitely is a problem that needs to be squashed. So the more technologies out there trying to squash it, the better.

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A new spam blocker called Defensio is attempting to improve on the standard set by Automattic’s Akismet, the default blocker for WordPress.

Defensio boasts a few features lacking in Akismet, most notably the ability to sort your blog’s blocked comments by “spamminess” so you don’t have to wade through them chronologically to find false positives. Defensio will rank comments that it labels as spam according to how likely it thinks the comments are indeed spam, listing the least likely comments on top. The blocker will even color code your blocked comments to help you find the ones you want to approve.

Defensio also adapts to the content of your blog so that it can target spam more effectively. It’s success at blocking the right comments for each individual blog can be tracked, so you’ll know just how well Defensio is performing for you.

Among Defensio’s other innovations is an open API that makes the blocker available for use with non-blogging applications. Defensio also provides RSS feeds for your comments (sorted by spamminess, of course) so you can track them outside of your publishing platform.

Today, the company releases plugins for both WordPress and Pixelpost, and they may release one for the CMS Umbraco as well. Plugins for Rails and .NET developers will also be available. Defensio plans to develop plugins across a wide range of platforms over the coming months.

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