The purpose of advertising - to sell shit, right?

So I'm driving to a friend's house for Halloween festivities. As I'm making the turn from I-10 West onto I-17 North I see a big black billboard with white text.

"Are you as backed up as this traffic?"

There's a website listed but I'm not going to provide them with publicity. They setll a product that helps with constipation.

But yeah, after a fashion - they're really selling SHIT.