Pete Blackshaw wrote a thoughtful column last week about the dangers of making "friends" too easily on social networks such as Facebook, LinkedIn, and the like. The invitations come fast and furious, and it's all too easy to just click "yes" to accept the request regardless of how well you really know or care about the person doing the inviting. It's flattering, and the connection might come in useful at some point. As Blackshow noted, though, "at some point, you can't just say "yes" blindly. Friendship comes with obligations, responsibility, and some level of accountability."

It's certainly true that gaining value from social networks is difficult if you close yourself off from actually networking. And if you limit yourself to just accepting invitations from people with whom you already have a strong relationship, you're highly unlikely to learn much of anything new. 

But the promiscuity of so many of today's networks is a main reason why business executives are generally slow to get involved. They have even less time or tolerance for phony friends than most folks, and are extremely wary of opening their virtual doors to unwanted suitors.

That's why, as I suggested recently, the most successful online communities for executives will be the ones that build off face-to-face activities and groups. Social networking will no doubt continue to grow across executive-level communities. But keeping them focused and protected will make all the difference.