The phrase "For those about to rock, we salute you" is a variation on the words "We who are about to die to salute you" which is what Roman gladiators would say to the high rulers before fighting to the death in the arena.
AC/DC is easily one of the most well-known and loved classic rock bands in the world. They have 15 albums, most of which went platinum in almost every country. They're known for their hit songs Highway to Hell, Back in Black, and Thunderstruck. A household name in the '70s, '80s, and beyond.