What does it mean when a website is "powered by google adwords"? To explain the question in context, a webiste can offer their advertising service for free, because they are "powered by google adwords"?

It not talking about the website being powered by google adwords but rather that block of where it says powered by google adwords are adds that other company's pay google to show on hundreds of pages. People pay google every time someone clicks the adds for a negotiable amount.