The Full form of FYI is For Your Information. FYI is an internet slang commonly used these days on online chatting. It is also used through email or printed paper while sharing information with friends or colleagues. It specifies a situation in which one person wants to share information with other person. The message or information provided using FYI normally does not ask for any immediate action, it is information that is additional to supplement the main message or information.

So, “FYI” is used commonly in instant messaging or memo, email, and messages, typically in the message subject, to flag the information or message as an informational message, with the intent to communicate to the person who may be interested in the topic, but is not obliged to reply or required to perform any action. It is also commonly used in business spoken and informal conversations. It is considered informal to use FYI in conversation. Sometimes, it also seems arrogant and disrespectful if it is not used properly. So, it is advised to avoid FYI in any kind of formal or business conversations. For example, if a person says can you please send me the brochure of product, then an online retailer might say that sorry sir, FYI, we are out of stock.