It's both, and more.
You can't ever have everything, especially when it comes to humans. Create something new like the internet and as soon as it catches on it'll be used as much for frivolous or sinister things as it will for useful things.
I'm not so much bothered by being forced to look at people's dinner, or their children photographs on Facebook as I am by governments desperately trying to control everything. For a wonderful 10 years the internet was quite "free", but not any more. Now you can be arrested for saying something out of context on Facebook, making a terrorist joke on Twitter, etc., now prospective employers try to look you up on Facebook to see what you are 'really like', (aka snoop) and companies get to legitimately steal the photos of people who use their services... and soon they'll be trying to find ways to filter what you can see or what gets to be allowed on the internet or tiering access, if they are not doing this as we type. The very thought that people can be anonymous, can find unvetted information on the internet, that child might see a piece of porn, or can publish any opinion or material they like must scare governments and certain other people sh*tless.
But I don't recall the internet at any point being some bastion of the significant as opposed to the insignificant. The very first web page I looked at when I first ever used the internet - Catlord's Tekken site in 1998. And it was filled with all kinds of random crap back then as much as not. It's always been filled with it, but what was important was that nobody was telling you what you should or shouldn't see on it back then. The randomness and potential uselessness of what people do on the internet is part of what "freedom" is (and I'd much rather have that than the vision of it being suggested by those in power)
What makes people so addicted to social networking is a good question. I have no idea because Facebook bores me to death. I only remain there in the hope I can promote my business on it, and to use the chat function to speak to my significant other during their lunch break at work because sadly no other sites like Skype function there. I think the novelty of Facebook wore off within weeks of me joining it, and Twitter even faster than that. Unless I was a celebrity or some person of note, why does anyone care what I had for lunch or about my kids or about whatever? And they usually don't. Maybe I don't have as close knit family or friends as some people but I do know people on there obsessed with documenting just about everything on there. And it turns out they are the people with a lot of money to show off or people with nothing else to do. And they don't seem to care that Facebook could take those pictures or that it's still set to quite public. If I had to guess besides it being a convenient way to communicate these days (though my family still can't be bothered to send me a 5-second FB message or email, lol) that there's some kind of chemical reward in the brain every time someone gets a 'like' or a 'message' on there from a post. Logging in to see if anyone's "said anything". Maybe our modern lives are just this dull or I am not getting it at all.
Or maybe it is people just plain showing off.
I have never been into showing off, I even find it a little difficult showing pictures of my artwork because I figure "who will even want to see this or want to buy it anyway?" in the back of my mind, but so many people now seem to have no problem whatever with showing off what they have just done all day on social media, so... it is probably just "me" and a few others who think it's kind of lame. Most people seem to think it is great.