Security Blog MCWResearch was hit by a large amount of spammy posts over the past day. It turns out the blog allowed posting via e-mail, and this feature has been subsequently disabled. I wouldn't be surprised if we see an enterprising spammer search for populations of e-mail to blog gateways. They can use their preexisting infrastructure to push spam into a new direction. Remediation for the population would be trivial, as e-mail-to-post functionality is not critical for the functioning of blogs.
Lesson learned: don't allow unauthenticated access to services unless you are required to do so (inbound MTAs, public web servers, etc).