But 2 points you didn’t raise, and I wonder why (because I am sure they aren’t new to you):

1. The ‘giant echo chamber’ is true for smaller orgs with low turnover, but in any org of sufficient size/complexity, there is enough turnover, role flux etc. that the internal social network adds value simply as a huge, dynamically updated org. chart, to let people maintain a real-time situation awareness. Right now, I periodically get some org. chart updates as emailed PPTs, and go dig out (usually obsolete) charts when I need them. It usually takes a phone call to clarify work history and context in interacting with a distant corporate peer for the first time.

2. Maybe the echo chamber doesn’t matter, because ideation and innovation isn’t what you are looking for at all for this particular medium — maybe that function is happening elsewhere, in the innovation portals etc., with sufficient injection of outsiders (customers etc.) to keep things fresh. The true value I think, may be in the ‘deep work history’ aspect. Example: one major customer of ours, a defense firm with multiple business units, uses a homegrown social network of sorts (actually, one of those expertise locater thingies of the KM era) very effectively to keep track of people who worked on large military contracts through their lifecycle. Such huge projects are like very fluid internal sub-corporations that are born and die with 5-30 year life cycles. A huge number of people flow through such efforts, and keeping track of who did what and when on a megaproject is of huge value to this customer, and something even a very good org chart system just doesn’t capture. When internal social networking capabilities finally mature, this will be a function they’ll need to take on that will need a fairly significant redesign of the ‘public’ models like LinkedIn, which profile expertise and work histories at much shallower levels (i.e. ‘Mechanical Engineer, worked at Acme Inc. 1993-98′ as opposed to ‘Knows the K3233 Pro Widget Circuit Board, and was on the HugeDeal project during Phase II’)

Satire is the highest form of comedy.

Seriously, though, I think the concern is valid and it’s possible that it would inevitably happen once, maybe twice. Consider it a cost. After that it wouldn’t happen any more, just like the common axiom for men saying the best way to remember your anniversary is to forget it once.

Boy. I can just hear the jaws clenching in the legal and HR departments about the ease with which a person might accidentally share a confidential item. Hmmm.

However, I think external social networks are paving the way to internal ones, and companies will eventually realize that, and implement it. The most important catalyst for such adoption would be security – already we’re seeing a lot of corporate information flowing freely in Facebook, Twitter, MySpace, Xing and others. In Israel a soldier (at an intelligence unit) was sentenced to 21 days detention for uploading pictures of his military base to facebook.
I’m sure security officers at businesses are searching the social web like crazy for internal (and maybe even confidential) information.

As more employees are using external social networks, this concern will become more and more real. And that would induce the introduction of internal social networks.

Aditya, exactly. Online social networks should only live in a company’s DMZ, perhaps…