I think this is just changing the way the younger 'facebook' generation think, posting becomes less personal and more about how you like to be perceived. Those of us that grew up without facebook embraced it as a nice way to share personal items with our friends.

Now it seems more of a PR stream, people staging photos for facebook, carefully updating status's knowing that a wider audience can see.

For me timeline represents facebooks focus on a single identity that you control, rather than representing who you actually are.