There's no such thing as online privacy - privacy is dead.
It's better that the default for most things online is public since any privacy setting is just an illusion of security. Of course there are some notable exceptions to this (encrypted backup services that encrypt locally before backup), but for the most part if it's online and at least some other people can see it - everyone can see it.
It took me a loooong time to figure out how to do privacy and social networking at the same time, using only web technology. Actually it can't be provably private using web technology because you have to trust the server -- which is why we need this: http://news.ycombinator.com/item?id=2024164
using encryption it's completely possible to make any information exchange as secure as it can possibly be without accounting for humans on the other end leaking the information.
There's no such thing as online privacy - privacy is dead.
It's better that the default for most things online is public since any privacy setting is just an illusion of security. Of course there are some notable exceptions to this (encrypted backup services that encrypt locally before backup), but for the most part if it's online and at least some other people can see it - everyone can see it.