In the last few years a new player in the music biz has come on the scene. But it's not really part of the music biz. It's outside of the music biz, because it's not a business; it's not a music venue trying to make a profit. To call it an underground revolution taking place may be an exxageration, but maybe not. It's the house concert.
What's a house concert? Someone invites one of their favorite singer-songwriters to do a concert in their living room. They invite friends and the performer publicizes it, mostly via email and websites. You bring food or drink as in a potluck, and a donation is requested for the performer. The performer keeps 100% of the donations, and also can sell cd's. The host doesn't do it to make money, they host because they love the performer and want to turn other people on to them.
I love house concerts. Typically everyone comes an hour early and socializes, eats snacks and drinks. The performer is right there in front of you. Some house concerts are unamplified. It's like going to a party where someone breaks out an acoustic guitar. Except instead of someone singing "Margaritaville" out-of-tune, it's a professional singer-songwriter singing original songs.
It will be interesting to see how this "underground" trend develops.