Definition: Favoriting (or "Twitter Favorites") is an action taken by Twitter users to express appreciation for another user's tweet and bookmark it for future reference. Comparable to "liking," favorites are another form of Twitter engagement where users click on a star-shaped icon under the tweet.
Favoriting is a subtle way to engage followers, more effective in many circumstances than directly replying. In many ways, Twitter has become more of a broadcast platform than a network. People, businesses and organizations flood their followers with a stream of content on a daily basis, usually accompanied with calls-to-action. Retweeting is another form of active engagement and can be used in tandem with the favorite button.
Even replying to a tweet can be perceived as overly self-promotional, but favoriting a tweet is much more subtle. When new prospects tweet about products you offer using common hashtags, favoriting acknowledges the comment and can distinguish you from other direct marketing efforts.
Twitter users know that businesses use pre-planned tweets, but favorites can only be done manually and convey a higher level of engagement. Active listening makes a powerful impression on Twitter followers who are accustomed to a bombardment of direct marketing messages.
In addition to expressing simple interest, favoriting has several other implications depending on contextual use.