Google gets a customer and free advertising, the company gets 100k worth of free computing resources. It's called a "win-win." It's not quite a "free lunch," but it's "one of the main ways in which healthy business gets done."
Not to nitpick, but the site states $100K for 1 year, which seems like a "use or lose" type deal. So if your start up doesn't burn through that much in hosting/storage/computing, you aren't really getting $100k in free computing resources.
