Talking about Facebook, LinkedIn, Twitter and all the other social media opportunities for virtual networking without any face-to-face contact. But what about the breakfast meetings and seminars where you can meet real people and not their polished Web personalities? Two-way conversation face-to-face seems to me a much better way to present yourself or to meet others when you are offering professional services.
If the key factors to evaluate are credibility and integrity it is much easier to fake it on the Web than in person.
I'm not suggesting that online media cannot be helpful, but they should be complementary to other real-life expressions of your individuality and unique skill set. In particular, make your online presentation more real and personal by adding original content in your own words and include audio or video to complete the picture.
It all takes time and effort, so it's important not to waste time on unproductive networking opportunities or to participate ineffectively.