I can't see how that is possible. What if your employer is looking for someone? Wouldn't they see your post?
Here's how I do it...
My LinkedIn page is very public. I know this. I also want it- I am willing to be transparent with a potential employer (or anyone).
When I am job hunting, I make a few updates to my page. I never say anything specifically about job hunting, but it begins pinging people because of my activity.
Then, I sign up for the basic paid subscription- I think it's $19.99 per month. That's pretty cheap. It sends me notifications of companies looking for someone like me. I follow these leads diligently, and invite any of them to view my LinkedIn page (like a secondary online resume). When they view it, I am notified. I pursue these leads even more diligently.
I also join groups, and participate intelligently. It increases my exposure. I follow what I can from those.
I also seek invitations to private groups. When I know someone is in a relevant group, I ask for an invite. Then participate (cautiously). I don't want to overdo this.
I also attempt to connect with every lead I am able to. Again, cautiously. I don't want to look like I am trying to grab their contacts and mine them for data, but if the opportunity presents itself, I will grab their contacts and mine them for data.
I request confidentiality in every contact I make. Never had an issue. In fact, they seem to view the request as an indicator of my professionalism.
When I find what I am looking for, I unsubscribe to the paid version, and stop participating in groups. It dials down the noise again.
Note: my industry doesn't use headhunters. If it did, I would contact them directly.
I don't use it like it is a billboard, staring in the face of every possible contact. I want better quality leads then that. For me, it's more like fishing. Play the line, patience. Play the line, patience.