Well its main competition doesn't really need any advertising cause they come standard in the OS, which in some way you do pay for it. And then most other browsers are also closed source.
I see this like a band street team. There are people who go out and spread the word not because they're getting paid, but to show their support. Of course there are those teams who get shit for doing stuff, but you don't get anything from spreading this around. It not like they used any really dirty tactics, unless you think telling people to spread the word is dirty...