The Dojo is inviting them to work with passive candidates who are members of the Dojo in a positive framework: ie, by sponsoring the Dojo and getting attention that way instead of by spamming people.
Multi-billion $ industry ripe for disruption. I have (will and continue too) take much shit with my current and past firm(s) (leaving out current employment as I must take a "this is my own opinion etc." stance), on posting to corp Yammer or Chatter pages: Please do not spam 4,000 candidates cross-state with "Django" somewhere in a profile via mass-mailing. It hurts the brand, angers candidates I work with (sometimes for a few years, or who are already working on a project), etc." All pushed through mass Chatter or Yammer, hence visible to higher ups, going "who is this Recruiter with some smattering of negativity?". /stirs the pot.
Perhaps I'm missing something with what this accomplishes (trying to understand as a Tech Recruiter (not for long however)). Majority of spams of course = a cruddy Boolean string (or worse, 1-2 key words), selecting a few hundred people and template spamming messages. Without reviewing notes or even resumes.
I imagine this is local :)
It is effective "throw crap at wall" until 2 candidates fit for a hire.
If you're not interested in some recruiter, just don't reply.