Damien, Janet Jackson's legacy is the modern dancing female singer. She popularized elaborate dance performances among female vocalists. Every female singer who dances in addition to singing (Ciara, Beyoncé, Mya, Aaliyah, Britney Spears, etc.) owes something to Janet.
The 
janet. era has been recognized for contributing to the further sexualization of Popular culture and society in general.
Lastly, she's iconic.
- "No, my first name ain't 'Baby'. It's JANET; Ms. Jackson if you're nasty!"
- The cover of the Control album
- The What Have You Done for Me Lately video
- The Pleasure Principle video (Me & U)
- The Rhythm Nation video (Ring the Alarm performed live)
- The Love Will Never Do Without You video (my avatar)
- The Alright video (Yeah 3x)
- That's the Way Love Goes's video
- The 1993 Rolling Stone cover in which she holds her hands above her heads while her breasts are restrained by an unseen man's hands - which has been copied MILLIONS of times.
- The Scream video (I'm Out)
I mean, this is just common knowledge. She is just as legendary as her brother, Madonna, Stevie, etc.