Anything you write has an automatic copyright on it. Even a love letter to a friend or girlfriend. Hubpages for one is a site that allows tou to put your written work on the site for others to see. Thus noone else can copy your stuff once it is written and published.
Having said that you can't copyright somethiing like 'a red balloon' or 'my sore knee' because they are too common. Anything you write that is completely original cannot be legally reproduced in the exact same form