Protection rackets seem easy to run on the internet.  While that example is pretty large scale; there are plenty of smaller opportunities for this kind of criminal activity.  Another long tail.  This morning this got caught in the blog’s spam filter:

hello , my name is Richard and I know  you get a lot of spammy comments ,  I can help you with this problem . I know a lot of spammers and I will ask them not to post on your site. It will reduce the volume of spam by 30-50%

He goes on to provide an IM contact and suggests the payment would be, only, some link juice.