In text messaging and online communication, FTW is an abbreviation that stands for "For The Win". It is used to express enthusiasm or approval for something, and it generally has positive connotations. People use it to show support for a sports team, express excitement about an achievement, or show appreciation for something they like. For example, someone might say "Pizza FTW!" to express their love for pizza.
It is important to note that in some situations and subcultures, such as biker culture, FTW can alternatively stand for "Fuck The World". This is almost the opposite of the more common meaning and is used to express sadness, disappointment with something or someone, or a rebellious spirit. However, the context of the message should make it easy to interpret the meaning, and it is usually clear which meaning is intended.