Google doesn't advertise. That's OK, Microsoft didn't advertise for years. But their reasons for not advertising were different.
Gates, being a geek, didn't think he needed to advertise. Like all programmers, he figured, if you don't like my code, hey, don't use it.
Google doesn't advertise, because they don't have to. They know that every block they plug into that Great Mandala they're building, just makes the thing spin faster. And you're already on board.
Google doesn't have to tell you what to do. Google knows what you're going to do.