Now you don't have to "like" something to share it. A new breed of apps will tell your friends what you read, listen to and watch -- because when you sign up for them, that's what you give them permission to do.
As far as seismic visions for the Web, this is one of the big ones. Think about it: Everything you do online, shared automatically. And Facebook keeps a running log of it all.
Creepy. The Ticker and Timeline affect even those who don't spring for such apps. The "how to opt out" tips here make this a keeper.