Facebook are going to very soon launch subscribe buttons for Facebook profiles. Facebook launched the "subscribe" option to Facebook profiles back at F8 which enabled anyone on Facebook to subscribe to another person's update, providing that person activated the feature. It allowed people to be subscribed to, without having to be friends with them.
This subscribe feature is literally the same as following someone on Twitter. Facebook launched this feature to directly compete against Twitter and with the launch of subscribe buttons which can be placed on a website, Twitter have got some real competition.
There is no confirmation on when the buttons will be launched but Facebook say it's coming "soon".