IMO, the majority of people in the world are interested more in their "social" social network than in their "business" social network.

This is true, FB's volume potential is higher than LI. But it is also true that those people who are interested in their "business social network" are accustomed to paying for services that create business value, sometimes paying handsomely. Those people interested in their social network are less accustomed to paying for "social services", and may be less able to put a value on the service (telecommunication services excepted).

It's not clear either that someone couldn't implement a LinkedIn clone on Facebook's API. FB isn't ignoring the corporate space, for example their "networks" feature is tied to a corporate email address anyone who is a member of a company network, you can trust that their identity is real. LinkedIn is even trying to get in on FB's turf, with its status updates.

On the other hand, advertisers tend to want to advertise to the people interested in their "social social network". Advertising to job seekers is inherently limited.

Agreed, but you're less likely to find falsified information on a LinkedIn page. The people on LinkedIn in are more likely to be real. That has considerably more tangible value IMO.

If you mean name, gender and location, then yes, those are less likely to be falsified. Everything else - everything that actually matters such as job titles, job descriptions, recommendations - is just as unreliable.

I personally know many people who lie on their profiles. One of my former startup partners lists herself as a CEO, except we were never structured that way, and she was never the top in command. People inflate their resumes all the time - if they have a one-man consulting company, they are the Lead Architect, if they received options as part of their incentives package, they are a Founder, etc.

Just look at all the recommendations. Literally everyone is Bill Gates and Mother Theresa rolled into one. I have yet to see a recommendation that simply says, hey - this guy is a competent programmer. Everyone is "world-class", "exceptionally talented", etc.

In contrast, none of my friends falsify personal information on Facebook. The incentive simply isn't there.

Can you explain what about Facebook is inherently dangerous to a career? Perhaps what some people put in their profiles would be damaging, but even that depends on what their field is, and how controlling and employee image focused their employer is.

Serious question: what do you do on linked in? What business value do you get?

I know several recruiters and speakers who use LinkedIn with great success. But outside of those two fields, most of the people I talk to use linkedin as a glorified rollodex and nothing more. I would be really interested in examples of what you have used it for.

It's more than a glorified rolodex, really. With LinkedIn you get much more of a "push" approach to business networking, whereas the rolodex and telephone model is much more "pull" based.

I can examine the profile of someone I've worked with before and know before I contact them if they know someone with whom I'd be interested in connecting. I can get notification that they are changing jobs, looking for work, or trying to find someone with a specialization, and they can notify other people at the same time. The rolodex and telephone model make this much harder, and so normally suchnotification happens far later, when you call to otherwise just keep in touch, unless the matter is otherwise extremely urgent.

It also serves as nice electronic substitute for resume and references. There's nothing for you to lose, and it allows you to update both in real time, avoiding the need to submit a new resume and list of references to potential employers whenever you want to add something new.

I know that at the last couple of places I've worked, part of the recruitment process was looking over my LinkedIn profile -- around the time I was being considered, I got notification that someone from the place I was applying had viewed my profile. I don't know whether it helped in my case, but I can't imagine they would even bother if it was always a waste of time.

Virtual business cards / online rolodex. When you're running a company your business contacts are super important. So every time that I get a business card in some context I look the people up on LinkedIn, then I can also see more about their background, and I don't have to worry about losing their card or adding them to my address book.

Incidentally, I didn't get LinkedIn before starting a business either. I'd even canceled my original account because I found the deluge of people that I saw at work every day adding me as a contact rather silly. Now, though, I use LinkedIn (or its European competitor, Xing) several times a week.

I have a LI account, but I don't use it effectively, so I can't speak from personal experience (which speaks to your point)

But I do believe businesses like Angstro could build a valuable business off LI (they could build it off FB too, but the value is much less obvious). This is, of course, an in theory statement, not an in practice one. Presumably LI could add Angstro like features themselves?

http://www.techcrunch50.com/2008/conference/presenter.php?pr... (I have no affiliation with Angstro)

I've picked up a couple of consulting gigs through providing decent answers im the Answers section.

If I have a few moments spare at the end of the day, I'll look through open questions and answer them. Sometimes they are interesting questions that I would like to think through myself; sometimes they land directly in my area of expertise. But it's a win-win you help someone, and at the same time advertise that you are a reasonable, helpful guy who knows at least something about an area.

By comparison, I find Facebook completely pointless.

I've used it to look up customers, and people who work at various ISPs I was dealing with. I've also used it for the post-conference lookup to solidify connections that were made in person.

It's main utility to most people comes in the job hunting phase, but I've found it useful for building and maintaining weak ties with lots of people.

I'm always looking to grow my network, my public profile is at http://www.linkedin.com/in/laprice

Both in job hunting and filling positions. It goes both ways. Rather than trying to capture everything social it has focused on just capturing the career network and doing it well. If I'm on LinkedIn it's for a reason: Jobs.

If I'm on Facebook it could be any number of reasons all of which probing raises privacy concerns.

So, how often are you on linkedin then? every two years? Or how often do you change jobs?

Depends, like I said. I've used it both in job hunting and filling positions that are open. In the case where I was job hunting I did searches on the people who interviewed me either before (if I happened to know who I was meeting with) or after the interviews.

I even searched for people I didn't interview with, but were listed as having worked for the same company with similar job titles. It's a good way gauge the caliber of the people they've hired to work there.

I used it to find out that I knew someone that knew a CEO-type at a potential acquirer. That was cool.