This duet between a lonely robot girl and a human boy marked Porter Robinson's vocal debut. He used Vocaloid, a synth that recreates the human singing voice, for the female part. "I'd used Vocaloid as the vocals for several of the songs on Worlds, and then the idea of a duet between a lonely robot girl and the human boy who encounters her occurred to me," Robinson explained. "I didn't have much time before I had to turn in the entire album, so I just sang the male parts. I wanted something that felt distantly sad, a little cute, surreal, hopeful, and maybe somehow evocative of fiction."
Another song about a robot's relationship with a human being is Royksopp's "The Girl and the Robot." In this instance Swedish vocalist Robyn sings about an ill-fated romance between a girl and a robot. Robyn also explored the idea of a futuristic synthetic mate on her solo single "Fembot."
"Whole Lotta Love" was Led Zeppelin's only US Top 10 hit, charting at #4. Many of their songs, including "Stairway To Heaven," were not released as singles, as it was considered bad form in England to make people pay for singles that were on albums.