I found Zevia at Mrs. Greens All Natural Grocer, and after hearing so much about it, I had to pick it up. Zevia is supposed to be the "Natural Alternative to Diet Soda." It's made with the natural, high intensity sweetener Stevia, which is currently considered to be an "additive" since the FDA hasn't approved it for use in foods & beverages (there is an excellent article on Stevia over at TreeHugger).
Nevertheless, Zevia, which is marketed as a "carbonated Stevia supplement" (because Stevia cannot be used as a food ingredient), managed to make it to the supermarket shelves. I picked up a can of the Natural Twist flavor. It has a lemon/ lime taste and a strong carbonated taste. I didn't detect much after-taste like the folks at Bevnet did, but there was a slight left over acidic taste on the back of my tongue - this might be due to the carbonation though. As sodas go, this would not be a favorite of mine.
There are no calories, and the ingredients are triple filtered carbonated water, natural erythritol, citric acid, natural flavors (lemon oil and lime oil) and stevia (leaf).
One can cost $1.30 - although the cashier tried to charge me $6.99 - for 1 can! I think people who would enjoy this are really concerned about artificial sweeteners, but still want to enjoy diet soda - are there people like that out there? Otherwise, the taste didn't wow me, and I much prefer Sprite Zero.