Wow. Some great responses on the Blue Security thing.

I've learned a thing or two about it and my animosity is somewhat dampened. I apologize for any offense I may have caused with my zeal and energy (it happens).

My still-looming concern about Blue Security's tactics deal with the scenario of the spammer that doesn't provide the option to opt-out or the spammer who only pretends to support opt-out but, really, ignores all requests or uses those requests to validate the e-mail addresses. I believe these scenarios may result in network abuse.

I applaud Blue Security for thinking out of the box, but I don't think we are quite there yet.