Please see the post on Plagiarism Today that was linked to from one of the pages you mentioned above:
http://www.plagiarismtoday.com/2008/09/11/backtype-republish...When I comment on TechCrunch or 37signals, I don't give them the copyright to my comment. I (implicitly) give them a license to republish the comment on their own website. However, I've never given Backtype a license to republish my comments on its website. Even if TechCrunch or 37signals chooses not to opt out of your system, you still don't have any legal rights to republish the comments.
From the commenter's standpoint, does it make sense to let you republish my content? I think the answer is emphatically "no." If I republish my own comments myself then I can also monetize them myself. If I build a WordPress plug-in to assist others in doing this, and/or if I build an OpenID extension or robots.txt extension for making comment streams more discoverable, then I can help form a user expectation of "If I want to see all the comments by John Doe, I can find them on John Doe's website." Then all the John Does can decide on their own how they monetize their own content on their own website (e.g. AdSense).
Consequently, really you are in direct competition with the people whose content you are re-publishing. AFAICT, you are saying "we're going to profit from your content without compensating you, regardless of the copyright, and there's no way that you can opt out except by refusing to publish new content." That sucks.
In the posts you linked to, you are comparing yourself to search engines like Google. The difference between your company and Google is that your company republishes the content in full, but Google provides just a small clip of the content. Google has a fair claim that what they are doing is fair use. Their limited excerpting of content is also what allows them to use an opt-out model instead of an opt-in model. That is also what makes it is easy for content creators to profit from Google's indexing of their content--Google users have to click through to the original site to see the content. You are just re-publishing the content in aggregate form.
I'm also curious about whether you think the DCMA safe harbor provisions apply to you when you are republishing others' content. As far as I can tell, they cannot, since you've really just built an automated plagiarism system. That is, there is no user-submitted content on your site; all the content published on your site is published by you yourself.
Anyway, if you really didn't get the message I sent your company, it boils down to this: Please remove everything I've written from your website, or come up with a means of fairly compensating me. Thank you.