Looking at the available info a bit more it looks like they are planning to insert adverts into the pages you view rather than emailing you spam.

As someone who runs a website, I am not happy that someone might then put adverts in my page before delivering it to the users. That is unacceptable as users may assume the adverts are part of my site when I have no knowledge of them as the page is on my server ad-free but could be delivered including ads that I have no control over.

Lets hope some techie genius figures out a way to stop this from working.