Americana is an interesting entity. The best description I could find is here:
Americana is a catch-all genre that takes in artists from folk, blues, country, R&B, rock and even a little jazz. What is most special about the genre is that they respect and provide exposure on the airwaves to veteran artists who long ago lost the ability to get new music played on corporate owned radio stations. While artists like Eric Clapton and Elton John fall into Americana on occasion, it also takes in greats like David Bromberg, Chip Taylor and Marcia Ball who put out albums that cannot get the exposure needed to cross over to (or back into) the mainstream."
The extensive "Top Albums of 2011" list includes Elvis Costellos "National Ransom" to Hot Tunas "Steady As She Goes". Just a giant weird listing of semi obscure. Pretty cool none the less if only to discover something you may otherwise be unfamilar with.
Here are the top 5
01. KMAG YOYO – Hayes Carll
02. Blessed – Lucinda Williams
03. I'll Never Get Out of This World Alive – Steve Earle
04. Paper Airplane – Alison Krauss & Union Station
05. Hard Bargain – Emmylou Harris