HASHING IT OUT: Facebook is introducing hashtags, the number signs used on Twitter, Instagram and other services to identify topics being discussed and allow users to search for them.

HOW IT WORKS: Users will be able to click a hashtag to see a feed of discussions about a topic. For example, typing a hashtag in front of "ladygaga" or "sunset" will turn the words into links to find posts about Lady Gaga or sunsets.

MORE AHEAD: Facebook said hashtags are a first step toward making it easier for users to find out what others are discussing. More features are planned.