The song's narrator describes four instances of encountering signs that anger or concern him, as follows:
A notice that "long-haired freaky people need not apply" for a job opening. He stuffs his hair into his hat in order to get an interview, then contemptuously reveals it once he has been offered the job.
A "no trespassing" warning outside a house. He climbs onto the perimeter fence and berates the owners for keeping people out and fencing in the land's natural beauty.
Being told to leave a restaurant because he does not meet its dress code or have a membership card, both of which are displayed on a sign.
A sign inviting people to worship at a church. When an offering is taken up at the end of the service, he makes a sign telling God that he is doing well, as he has no money to contribute.
"Signs" was covered and recorded live by Tesla for their Five Man Acoustical Jam album in 1990, peaking at number 8 on the Pop charts. This cover had some minor changes to the lyrics: the line "blockin' out the scenery" was changed to "fuckin' up the scenery," and "made up my own little sign" was changed to "made up my own fuckin' sign". A studio version recorded in 2007, which appeared on the EP A Peace of Time, used the original lyrics.
ApologetiX recorded a parody of the song titled "Lions", telling a Biblical story of a character named Daniel in a lion's den. It was originally included on the cassette of Radical History Tour, and was later re-issued on the "Director's Cut" edition of Isn't Wasn't Ain't.