So I searched online and came across www.tightlycurly.com. Terri LaFlesh, the author of Curly Like Me, has so generously put together this very informative site which includes an Ingredients Dictionary. Cha-ching! I spent an hour and ran down the ingredients lists of my products, comparing them to what Terri had researched and compiled into her online dictionary. After learning more about sulfates (among other ingredients) I understood why it's important for me to use a sulfate-free shampoo: sulfates are detergents that create suds when combined with water. Due to their drying effect, they tend to strip our naturally curly hair of its oils, making it dry and brittle. At least that's how I know my hair feels after using a sulfate shampoo. When I do use shampoo (I usually co-wash) I'll use a sulfate-free one. I've experienced much better results from my sulfate-free shampoo.
There are some benefits to using a sulfate shampoo, such as when your hair is really dirty. For example, the ONLY time I'll use a sulfate shampoo now is when I wash my hair after having worn it straight. Since my hair is loaded down with silicones from the heat protectant, the sulfates effectively remove the product so there's no build-up. Of course I follow-up with either my favorite moisturizing conditioner or a deep moisture treatment to replace the lost moisture.