The first dietary sweetener was made of saccharin (Sweet'N Low) when that was found to cause cancer, aspartame was next on the list (NutraSweet and Equal) no need to re-hash how horrid aspartame is for you. After it's fall sucralose was introduced (Splenda) which now has a pretty mainstream following against it, I think its on its way out permanently. Then after having been blocked by the powerful Monsanto company (who brought us sacchrin, aspartame, and agent orange) for 20 years, the Stevia plant comes into focus. Stevia extract is 300 times sweeter than sugar and can be extracted from the stevia leaf by methods similar to making tea. Truvia (made from the stevia leaf) is being released by Cargill and Coca-Cola. According to the Tuvia website, stevia is currently NOT being grown organically, for whatever reason.
synopsis
It will take a few years to understand the impact of this sweetener. There is currently a debate as to weather it causes impotence. No talk of cancer yet.
side note: in 100 years from now will Truvia be remembered as the all natural zero calorie sweetener that replaced sugar? or the next in a long line of artificial sweeteners that was later found to cause "something bad". These companies have not earned my trust, I'll stick to sugar.
Hope this helped.. or at least was interesting.