Privacy is concern of many users of social interactive platform like Twitter. Orkut introduced privacy features much to relief of its users and now Twitter is cleaning up with enhanced privacy features.
For people who have protected their profiles on Twitter expect to see changes like, protected updates will not be searchable or viewable by the general public. Also, protected profile owners must approve follow requests to allow new people to view their updates.
Protected profile owners do not automatically follow back when they approve a follow request. Also, profiles going from public to private maintain all existing followers and can remove them from their followers page at any time.
Get heads up on what is different now, How are things now and how they were before – check this Twitter Support link.