Memo opener, often

• "Oh, by the way ..." letters
• Memo heading, maybe
• "Just a heads-up," on a memo
• "Read this if you like"
• Memo ltrs
• Interoffice letters
• "I think you should be aware of this ...": Abbr
• Texter's "This might be of interest"
• Memo-heading inits

Wikipedia Word definitions in Wikipedia
FYI is an abbreviation of "for your information". FYI may also refer to: