Telephone.

LoveGame is still really popular and plays on the radio all the time.

LoveGame (even though it's one of my favorite Gaga singles + video), Just Dance (overshadowed by Poker Face), and Alejandro (not as successful as BR and Telephone and the video didn't help). In the world excluding the US You & I is practically non existent.

not Alejandro being #3, it gets played all the time on local radio

Telephone, Paparazzi, Just Dance, and You and I.

you n I

for me it's Just Dance. I always forget that the song exists.

Yoü & I is my fav Gaga's song. But its forgetablle tbh.

Voted for Love Game tho. lol. Don't even remember it was a single.