I don't see many people using it that way. As a recruiter I use it as a massive resume database of passive candidates. Sometimes you will see someone actively promoting themselves as "looking" with a status update but this is usually a contractor who is coming up for end of contract, someone unemployed, or someone being made redundant. As you pointed out the last people you would want to know you were looking is your colleagues if you are looking on the sly. They are also highly unlikely to pass along an introduction from a headhunter which is why I prefer InMail instead.

The bit at the bottom of peoples profiles about "interested in career opportunities" is mostly ignored by everyone so I wouldn't see it as a big deal.

I have the same problem with Facebook.

We've had little joy recruiting on LinkedIn - their job board is a nightmare to navigate and the features for responding to applicants are utterly broken IMHO. LinkedIn should stick to their core skills, they seem to fail hard when they try anything else.

Things like Facebook and Twitter seem far better suited to getting jobs / candidates.

I guess part of the idea is that you'll be able to keep in touch with your old colleagues after you leave your job, and contact them for opportunities in the future. LinkedIn is only a couple of years old, so for many people I guess that value won't be apparent yet.

P.S. Does this mean you're looking for a new job? ;)

Actually, LinkedIn is the only social network for which I have any respect. I was headhunted once, which got me to start a job search that landed me a much better job even though it wasn't the one that headhunted me.

I'm not going to start looking for a job by announcing it on my LinkedIn profile, but most decent companies know that the people they want to employ are not actively looking for jobs anyway. I still get feelers for opportunities from time to time, and I've even tried to turn some of them into opportunities for my current employer (we do contract work).

I can't say it's made me money yet, but it has the potential to do so, unlike essentially anything else I do online. I am also connected to people from every (tech) job I've ever held, including my college internship.

Actually, LinkedIn is the only social network for which I have any respect. I was headhunted once, which got me to start a job search that landed me a much better job even though it wasn't the one that headhunted me.

I'm not going to start looking for a job by announcing it on my LinkedIn profile, but most decent companies know that the people they want to employ are not actively looking for jobs anyway. I still get feelers for opportunities from time to time, and I've even tried to turn some of them into opportunities for my current employer (we do contract work).

I can't say it's made me money yet, but it has the potential to do so, unlike essentially anything else I do online. I am also connected to people from every (tech) job I've ever held, including my college internship.

I use LinkedIn extensively for placements. The job postings on LinkedIn are a complete waste of money and not worth doing. When hiring for Atlassian I find LinkedIn is less effective. Of the 11 placements I have made so far the stats look like so:
Seek Ad Response - 4
LinkedIn -3
Google Search - 1
Google Adwords - 1
User Group Post - 1
Database - 1

LinkedIn has been a great tool for me, to network and to find the right fit for the hard-to fill positions for the last 10 months.

I have had over 12 placements from LinkedIn; so if you are a recruiter look at it as a networking site, be patient and build relationships, it's not a job board and you will see that will have an impact on your search for the perfect candidate.

Ruben