Here at Google, we're about to start offering an API to our search-engine, so that people can programmatically use Google through a clean and clearly defined interface, rather than have to resort to parsing HTML.
I really hope they charge money for it. Especially if they do it as a pennies-per result web service. They'd help launch the entire infrastructure for such products, and it'd be a great additional revenue stream for them. Relevant info about their refinement of the Google business model is available over at The Paper That Shall Not Be Named.
Google side note: Didja know that Page Rank was named after Larry Page, not HTML pages? It's true. There's also a less lengthy, easier to understand, less interesting explanation of Page Rank's function, done by a third-party researcher.