The thing is, the signal on a social network like Facebook is not strong enough to overcome the noise and it would require that I spend precious time parsing through a significant amount of that noise just to reach the few rare bits of signal. I'm not concerned about myself over-sharing, because I have at least some reasonable sense of "is anyone going to give a damn and will this be of any benefit to anyone whatsoever". I'm more concerned with he deluge of other people's mundane daily lives. I don't need to be a receptacle of their stream of consciousness and I don't need the chore of parsing through it for anything useful.
I'm, frankly, a little offended that you are suggesting that snobbery is involved and that it has an element of "well, your commentary doesn't my my needs the priority, so it is therefore of no interest to me". That's hardly it, at all. It's more an issue of "I don't need to be bombarded with every trivial thought and action of your entire daily life and I would not bombard you with the same". News shock -- you are not that important and neither am I. And you don't need to post the constant stream of inanity to "keep in touch" -- assuming that you even need a third party utility to "keep in touch" (isn't that what email is for?).
For example, I finally logged into my Facebook account while posting this and here were the most recent updates that greeted me. Note that the age of every poster here is between 25 and 50. No, I'm not solving world hunger, but am I a snob for saying that all of the below is a complete waste of my time and that the only reason a person would post any of these things is that they either have keyboard-turrettes or are some degree of attention whore?
Do I have anything more significant to say with the same frequency of all these inane posts? Do I have anything truly earth shattering and mind-bending and enlightening that absolutely must be shared with a hundred people several times per day? No, I don't. So I don't post. I choose not to add to the noise that other people (presumably people that I am either close friends with or at least vaguely associated with) have to sift through. Interesting how that makes me a snob, rather than considerate.
* Someone posted a picture of their cat.
* Someone posted a picture of something really old in their freezer and asked if they should still eat it.
* Someone made a snarky comment about Obama.
* Several people posted links spamming projects they're doing (shows, events, etc).
* Someone posted their tarot reading (again).
* Someone said they should have been in bed an hour ago.
* Someone answered questions in some app about how tall they are.
* Someone said they saved a lot of money grocery shopping today.
* Someone liked Dial brand soap.
* Someone said the work day will never end.
* Someone said they "love being a mommy".
* Several people posted links to random stupid youtube videos.
* Several more stupid updates from apps (no matter how many you click "hide" on, there are always more).
* Someone said "that dream was different!"
* Someone made some vague drama-infused comment about their relationship or a friendship or something (I couldn't tell which).
* Someone said they can't wait for Friday.
Another way of thinking of this. I call my mom maybe once a month and talk to her for half an hour or so. The woman who gave birth to me. The woman who raised me. The woman who sacrificed a lot in life to make sure that I was fortunate enough to become the person that I am today. I talk to her once a month-ish. Just long enough to catch up on the most important things and let her know she's important in our lives.
I would not want a running stream of every action and thought my own mom made. Why on earth would I want one every hour or two from every single friend or associate I have. People overshare. Too much and too frequently. And too trivially. Whatever happened to going out and having a drink and shooting the shit with your friends? That's fine, every now and then. Keeping in touch when something big is fine. I don't, however, need to hear from you every damn hour on every damn thing going on. And they don't need to hear that from me, either.
As I said, people absolutely adore talking about themselves. They are attention-whores. They want to broadcast as much inanity and/or drama as they possibly can to the largest audience they possibly can and it's usually a one-way-street (though even more so on Twitter). If they had even one second of consideration for the value of their contribution and the value of their "friends" time, they wouldn't post nearly as much of the crap that they do.
And it's not just your buddy. Or the guy at work. Or the ex-girlfriend. Or the random dude you met at a convention that friended you when you got back home. It's the tech celebs. It's the tech industry darlings. It's Scoble and Kevin Rose and everyone else. Trust me, I've considered following the twitter feeds of some of these people. After all, they stumble on to some cool things and have some interesting thoughts to offer. But even with these people, the level of noise is just incredible. So much so that I stopped following any of them ages ago and don't bother to follow anyone anymore, because I know that for every interesting 140 characters I get from them, I'll have to pour through many thousands of characters of trivial crap (or even meaningless crap, when it's just semi-inside stuff between them and someone else).
My time and attention isn't more valuable than anyone else's, but that doesn't mean that it should be wasted, either. It seems entirely reasonable to expect people to have at least a little bit of a filter on their output with respect for the dozens or hundreds or thousands of people that are going to be subjected to their signal (or more often, noise) before submitting.
And yes, I realize the hypocrisy of my statement after I just sat here and wrote about a thousand pages. Sorry.