A "natural" sweetener, Stevia was approved for use in late in 2008 in Australia and the US and the first Stevia products are now appearing on the supermarket shelves.
It's not considered "artificial" and marketing for stevia makes much of it being 100% natural - which appeals to consumers - compared to aspartame or acesulfame-K which are often regarded as "chemical" and can't escape the cancer-scare rumours that have been circulating for years.