This is partly because it's an interesting trend and alternative to standard club tours, and mostly because it's about a good friend of mine.
Shannon Curtis wrote a book about touring the country over the past couple of years doing almost exclusively house concerts. Her book hit the top of the music business category of Amazon, and now
Huffington Post has published an article about it all.
One of the most important factors in this strategy is engagement. A far higher percentage of those who go to these shows become invested in her as an artist, so are more likely to keep following her career and buying her merchandise even if she doesn't come back to that particular town next time around. It will be interesting to see how well this could work for other artists as well.