Man did not weave the web of life, he is merely a strand in it. Whatever he does to the web, he does to himself. - Chief Seattle, Amerindian. pg. 10 - The Art of Looking Sideways, Alan Fletcher.
There's always so much written about how social norms can go out the window when the anonymity of the web or even the simple removal of a human face takes over. I believe it's a temporary state though, and as much as I am loathe to admit it, I think the rise of Facebook has done more to bring about social change over the web than any other service, placing a premium back on the connections we really do have, versus say MySpace, Friendster, or whatever came before which was mass convergency at the expense of intimacy.
Of course lots of people still choose to use Facebook in that manner, personally I like to keep things a little more closed. But I think we're just about past the idea that what is appropriate social behaviour somehow differs face to face versus online. What we do to the web - or on it - we do to ourselves, and when we reduce the connections we have down to a series of contact details and earning potential, we get nothing more than that in return.