This service has been spamming developers, harvesting emails from open source repos and then emailing them, advertising the service. Really not cool. Even though it looks like quite a cool service, honestly I wouldn't use them on principle. Here's the email I received: http://i.imgur.com/Kf9Nv3F.png
We were not advertising, we're inviting the hackers to join if they are interested to send they help requests from their communities based on their contributions. We understand that it's not acceptable by some people and that's why we're going to change that.
A lot of the SEO spam I get says "This is not spam" in the footer. I'm this close to just setting up a filtering rule that moves all such mail straight to the trash.
Serious question: are you going to stop this or just change it? Some of your other messages are unclear on this point.