Angus Young created the distinctive opening guitar part for "Thuderstruck" by playing with all the strings taped up, except the B. He learned the studio trick from his older brother George Young, who was the rhythm guitarist for The Easybeats.
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.