Who's following @jl John Lennon...

https://cs-people.bu.edu/azs/images/katherine_switzer.jpg
@runner261 Katherine Switzer
https://upload.wikimedia.org/wikipedia/commons/thumb/2/2e/Jean-Luc_Picard_2.jpg/440px-Jean-Luc_Picard_2.jpg
@picard Jen-Luc Picard
https://cs-people.bu.edu/azs/images/grace_hopper.jpg
@captain_grace Grace Hopper