For example when Facebook recently changed the format one of my acquaintances was outraged that anyone could look up the information they post on Facebook. They had been using the internet not realizing that it was a global network the entire time.
Another example is a friend of mine when trying to consider my preference to not be exposed to some of his interests decided to create a sub blog for such content. However he didn't realize that the sub content shows on the home blog.
The world is changing we need to be aware of the consequences of our actions off and online.