We need a more ephemeral social sharing system. Why not just delete things after a year?
Just as "the only winning move is to not play", the only way to ensure your information isn't on the internet (precluding hacks) is to not put it there in the first place.
Unfortunately that's not always possible. For example you're in a pub with your friends, and someone takes a group picture and posts it online. Even if you don't have FB account, you're there, and there's absolutely nothing you can do about it. Very annoying.
You could have a chat with them and see if they're willing to respect your privacy. Nothing much that can be done about strangers who do that though.
I've seen a few places that actively ban Google Glass (I think that was mentioned here as well), but there are no bans on camera phones in any place as far as I know. If a thing exists, it will be used after all. Original intent be damned.
Making computer that forgets is like making more and more fantastic cars that run no faster than a horse because some people feel uncomfortable with them going faster.
I personally hate forgetting and I'd very much liked if I could call up, a computer system and recall every bit of my life. Everything I've seen, heard, and any data from any sensors that were in my vicinity.
See e.g. http://archive.org/web/web.php