yes and no. I signed up but never gave them access to my contacts. To much info to hand out to hackers and Big Spammers. IMO
You know, maybe I'm getting old, (I am), because I see all this stuff about twitter, facebook, instagram and who knows what else is out there, and I don't feel like taking all the time to follow up on all of this stuff, it's just too overwhelming. I have a smart phone that I use for phone calls, some email and very little test messaging, just between family. I personally don't see the fascination with all of this, besides using time that I would rather be doing something else, and I own a home, so you know where a lot of my time goes, LOL. To each his own I guess.
Never sit around bored? Want something to occupy your time during your 20 minute lunch break at the office? (I wish I got lunch breaks lol). I definitely see people obsessed with it and taking it too far, but to me it's just something to occupy what little down time I have instead of sitting there bored. It's no different than looking at forums, or watching TV in my opinion.
Do you ever read a newspaper? Or watch tv? Or go on forums? Uploading a picture from your phone isn't much different than those things. It's just a different way to consume media.