(click to zoom in)
My guess for the second line, which was not cracked: Because everyone has the right words.
"Under the [new GM's] campaign, which is about half completed, each day a billboard in a different part of the country divulges a word (or a punctuation mark) in a message. A billboard in Arlington, Texas, for example, says "you." One in New York City shows a period.
The billboards also promote a Web site on which GM explains that it created the campaign to spread "a message so important we need the whole country to tell it."
But some Web visitors quickly found that most of the "secret" message is included in the site's source code."
The first line says: "This is the last time you will ever have to feel alone on our nation's roadways."