I was thinking about this exact same thing a while ago. My biggest problem with LinkedIn is that you can't enabled "Do Not Disturb" and prevent InMail. The chicken and egg problem is real, so is the monetization. Money from recruiters won't come until you have users, right? Would users be willing to spend a small amount of money for a yearly subscription (for hosting their profile)? First year free, perhaps?

I thought about allowing users to "opt-in" to the network when they are interested in being contacted. Privacy and data ownership are another big concern of mine. Should advanced users be able to host their own profiles (no fees ever) and connect to the network when they want to be reached for opportunities?