Bernard Lunn at ReadWriteWeb has an interesting post about the long-term role of LinkedIn as a business tool.  He thinks it could replace Outlook and SalesForce:

Like all social networks, LinkedIn is under pressure to "open up." They may be be able to push back on that front if they create enough value so that biz people decide to live in LinkedIn as opposed to living in Outlook and SalesForce or the equivalent CRM.

I disagree with the Outlook comment.  I think trying to be an email client would be a dumb move into an overcrowded market owned by the best in the world.  A CRM platform becomes a little more interesting, but I still think that it's not where LinkedIn needs to be long-term.

LinkedIn's value proposition, to me anyway, lies in its gigantic user base of business users and especially in the way that it validates people's claims to be who they say they are and that they actually do belong to the organization they say they do.  It's a unique value-add that I don't see any other social network doing.  And, from a business perspective, it's incredibly useful.  When you look at my LinkedIn profile and see that I work for Cisco, you know that I actually do, in fact, work for Cisco, because as part of the verification process LinkedIn sends an email to my Cisco address.  Same for professional groups within LinkedIn that I'm a member of, such as the OpenID group or the Business Intelligence group.  I can't just join as many groups as I want to, because my membership has to be accepted by the group owner.

This, to me, is LinkedIn's true value, and one that I really do appreciate and value.  It also makes LinkedIn recommendations valuable.  They now have such a large base of validated professional credentials that they could conceivably be the credit rating agency of credentials.  A broker for verified contact information.

This will become more and more useful as the Internet continues to decentralize.  While the network itself flattens and becomes more distributed, LinkedIn has the potential to sit on top of it as a trusted source of verified contact and professional association information.  This will be an extremely valuable role as time goes on because, to my knowledge, they are the only ones playing this role, and they are doing it well.

While you raise your kids to grow and protect their credit score so they can buy a car and a house some day, you may want to consider teaching them how to build their online reputation as well.  As of today that means A)  protecting their online identity (Google Juice) and B)  starting a credible LinkedIn profile.  A) has no signs of going away, B) remains to be seen as to its stickiness.