>>ubermo+(OP)
What do you mean? Is there a legal definition of "mainstream"? The Last Airbender is topping the charts on Netflix. That surely must be enough for me to be allowed to call it mainstream and that a reference to it is not obscure.
If you read the sibling comments they are trying to say NCIS is not mainstream at all since TV ratings mean nothing, making the opposite point of yours. You guys are impossible.