Serious Eats - seriouseats.com

Here is an entire site devoted to the dangers of aspartame (no calorie sweetner)
http://www.dorway.com/indexnew.html

and another one linking diet soda to increased weight gain

http://www.webmd.com/diet/news/20050613/drink-more-diet-soda-gain-more-weight

and recently Chapel Hill University linked diet soda to all sorts of complications (heart disease, diabetes, stroke etc.) you can probably just google that...

Diet sodas are bad for you in a bunch of different ways (but a lot of things are bad for us in a lot of different ways, we just choose which bad things we're willing to take risks with):

First, phosphoric acid is bad for our teeth. It doesn't matter if it's sugar free, the acids are still bad for your teeth. (There's actually more phosphoric acid in zero calorie sodas than in the sugary ones.)

Second, phosphoric acid is bad for your bones, especially for women. It can lead to bone loss by leaching calcium from your system. Women who are losing weight, underweight or post-menopausal are most at risk as are kids are are still developing their bones and teeth.

Artificial sweeteners mess with your satiety, basically you lose the ability to judge when you're satisfied or full. People who drink sodas tend to eat more without even realizing it, so as a weight loss aid, it may actually be sabotaging your efforts.

There are lots of other scary sites you there that you can read about artificial sweeteners and their safety, you can judge for yourself ... but these three items have nothing to do with which sweetener is used.

As a sometime treat, they should be fine, but as something that you drink by the liter each day, it's something to pay close attention to. I don't think diet drinks should be given to children at all.

I agree with cybele and Hogwild... drinking phosphoric acid is pretty gross, regardless of the sugar content, and it's important to be critical about what one reads on the internet.

avryan, for example - re. the "links" with diabetes and heart disease, I looked at some of the articles, and it sounds as though diet soda is associated with a number of other risk factors for those diseases, but no one has suggested that it causes them - it may just be a marker for increased risk. The word "link" suggests a cause and effect relationship, but none of the studies that have found an association were designed to look at actual cause and effect, only association.