Remember the "Become a Fan' button that used to what you would click to become a fan of a page you like. Well that is not going to be the case anymore. Facebook has introduced the 'Like' button instead.
Introducing the Like button
Starting today people will be able to connect with your Page by clicking “Like” rather than “Become a Fan.” We hope this action will feel much more lightweight, and that it will increase the number of connections made across the site
This is a significant step in the simplification of Facebook with the "Become a Fan" button seeming to tell users that they are now a fan and therefore a burden needs to be carried. All users need to do now is like a page and be able to follow it.
Once users’ click on the “like” button it shows up in the users activity stream.
Websites will also be able to add the “Like” button to their websites and offer customizations to users such as showing them which articles their friends liked and which restaurants they visited.