Used to express "I Love You" in different contexts. The ILY handshape is a combination of the three fingerspelled letters: I+L+Y (I Love You).
It is used to, often informally, express "I love you" among family members, as well as sometimes among very close friends, whenever appropriate. It can be used at parting, or used as a different meaning in contexts.
Variation of the movement. It is also used in Deaf Ameslan culture as farewell with love between loved and close ones.
Just for fun:
Image posted on FB (Feb. 15, 2019) by Michael Baker who found this near his home in Bernalillo in New Mexico, USA. No photoshop.
"Sometimes burnt LEDs can lead to something even better! [ILY icon] :D" -- Joseph Wheeler (Feb. 15, 2019, FB).
Written ASL digit for "I-LOVE-YOU" contributed by the ASLwrite community, 2018.