I think it's worth drawing out something from my previous post about permission based marketing: Privacy is really, really, important.
One of the key features of the system we are building (which I go into in more detail elsewhere) is the ability to decide which parts of your information you want to reveal and when.
So imagine you're getting a bit bored of your job with "BigCo Inc." and put your recruitment profile into the marketplace. By publishing only selected skills and experience information you avoid anyone from BigCo seeing who you are and the tricky conversations that might arise when your manager hears "Hey Bob, did you know Matt is looking for a new job?" Instead when a request to reveal your identity comes from a BigCo hirer you can turn it down.
You will have the tools to decide what you want to reveal and to whom. If you want to be really picky about who gets to see your full details you can. If you're desparate for a job you might say "Anyone can see this." Whatever you actually do, it will have been your choice.
In order to make an informed choice you'll need to know who is asking as well. How many times have you looked at a job advert and suspected that there isn't really a real job only an opportunity for an agent to harvest your CV and your personal information? You should be able to remain anonymous until you have verified that the opportunity is genuine and choosen to release your details.
Of course this kind of selectivity cuts both ways and hirer managers too should be able to decide whether they want to reveal their information to candidates and what information to reveal.
Both sides get to choose how much privacy they need to be comfortable interacting in the marketplace.