A potential problem with this approach would be competition: posters who are desperately looking for a job will keep trying to one-up each other with their accomplishments, and it could get ugly.
Although recruiters will probably go wild all over it and nobody really wants that, do they?
Surely if you include "No recruiters please." they will respect that? Or am I naive?
I put "No recruiters" on every single section of my LinkedIn profile, yet they still e-mailed. Eventually I removed every single detail from it. Even now I get the odd message.
They get a significant portion(10% or more) of your first years salary if you get hired. It's a numbers game and the more people they call the more money they make. They have a thick skin and the only thing stopping them from that money is a brief no from you. They will definitely try.