When browsing Facebook, the "Like" button appears next to many items. You can even like external pages or Facebook fan pages. The Facebook Like button is a feature that allows you to show approval or connect with another person or affiliation on Facebook. Sharing a like for a picture on Facebook essentially does just that -- lets the poster and tagged friends know that you like the picture.
Liking an Item
You can "Like" several things on Facebook including photos, status updates, videos and comments posted by others. The Like button appears next to photos or content posted by Facebook friends. When you click the Like button, it notifies the friend who posted the content or any individuals tagged in the content that you like it. Using the Like button is simpler than leaving a comment, yet creates social interaction. When you like an item a notification will also appear on your wall showing that you liked it.
Liking a Page
Liking a Facebook page is different than liking an item. Previously known as "Becoming a Fan," Facebook changed it to "Liking" instead to make it more consistent with other Facebook features. When you like a page, you essentially become a fan or follower of that page. Facebook pages can include business pages, brand pages, company pages or other affiliations. Updates posted by the Facebook page then appear on your Facebook news feed and you also gain the ability to post content on the liked page.
Liking Content Off of Facebook
Another way to use the Like button is on external websites that support it. When you click "Like" on an external page not affiliated with Facebook (when available), a synopsis of the page appears in your Facebook news feed and allows any of your friends to see it. This makes it possible to share news stories and other updates off of Facebook with your Facebook friends.
"Unliking" removes your Like status from an item. If you previously liked a photo, you can navigate back to the photo and click the "Unlike" button. Unliking does not send out a notification the same way liking does; however it does remove your like status next to the item. You can also unlike status updates, comments, pages or off-site content.