Sometime last year, maybe when IBM started flogging its reinvention of Lotus Sametime, vendors and CIOs alike started thinking that maybe this model for connecting people inside the enterprise would drive more collaboration and solve the conundrum that has bedeviled knowledge management advocates for as long as we've had a knowledge-based economy: Corporate intranets are just no fun.

Lightweight and intuitive apps that let people inside (and out) your enterprise connect with each other and discover each other's aptitudes and interests seem a lot more promising than using laborious taxonomies to code documents and write up lengthy biographies to help identify corporate experts on given subjects.

The emergence of networking sites devoted exclusively to professionals, like LinkedIn, Plaxo (with its Pulse network) and, to an extent, Facebook, have added fuel to this relationship-driven fire.

And as our Clint Boulton reports, it's the quality of the networks, not the number of names they contain, that will give them the most enterprise value.

But value is one thing, and enthusiasm is another. Now, I happen to love LinkedIn; I use it to find sources and possible collaborators, and to snoop around on my competitors. And I'll keep using this kind of networking tool because it makes me better at what I truly love doing.

But just because something's taken off in one context doesn't mean it can work in another. You might notice that there's not a lot of cruising going on in LinkedIn, which is as its designers and human resource executives would want. But that's precisely what's driven the consumer social networks like MySpace. Without any real sex appeal, I suspect that the enthusiasm for enterprise social networking will dry up in the long run.