I also watched a Jamie Oliver documentary series about food in the US and he managed to wangle his way into similar places in a few US cities (mostly oriented around Mexican food).
I don't agree with that, a lot of underground bands and artists use online only advertisement like last.fm and deviantart.com and still are underground.
It's just about the way you market it... you can narrowcast your marketing to only the people you wanna hit, so you keep the underground feeling but get more customers.
I also watched a Jamie Oliver documentary series about food in the US and he managed to wangle his way into similar places in a few US cities (mostly oriented around Mexican food).