Who are "They?"

My mother today said to me, "ya know, they say that a splash of red is really in this season." I looked at her sort of puzzled and thought, who is they? Or, well, who are they? Usually, when she says "they" she means anyone on the Today Show because whatever Matt Lauer says is the ultimate truth, but it puzzles me. Even as I watch Kathie Lee and Hoda in the morning, they will say, "Ya know, they say you have to wash your hands for at least thirty seconds." Or, "Ya know, they say it's ok to drink well before noon." Who is this "they?" Is there a group of people out there that call themselves "THEY" that get together every so often and have meetings and come up with these ridiculous "facts" and "trends." It's starting to worry me. They are influencing the world. Kind of like Oprah. I'm desperate to know who these people are. It goes across the board, even with movie or TV reviews. My mom and I were talking about the new Charlie's Angels the other day and she says to me, "they said that was awful." Who? Who said it was awful? Who's they? Cite your sources, people.