George Harrison's 1971 song "Bangla Desh" was the first major charity single. It was part of a concert held to bring relief to the people of Bangladesh, who were fighting for independence and suffering from a famine.
"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.
Robin Thicke and his mom, Gloria Loring are the first the first ever mother-and-son to have both tallied top 10 singles on the Hot 100 as solo artists or duos. Loring reached #2 with Carl Anderson in 1986 with "Friends and Lovers" and Thicke topped the chart in 2013 with "Blurred Lines."
Who writes a song about a name they found in a phone book? That's just one of the everyday things these guys find to sing about. Anything in their field of vision or general scope of knowledge is fair game. If you cross paths with them, so are you.