Can I just say that there are a lot of internet sites out there that are quite dramatic, for example -
http://www.naturesparadiseorganics.com/dangersofsulfates.html
This is slightly better -
http://www.treatment-skincare.com/Active-Ingredients/SLS.html
More & more people are reporting sensitivity to some ingredients, but just because some people react, it does not mean everybody will.
Right, to answer your question, 'sulphates' (sulfates USA) is being used as a blanket term for a group of harsh cleansing ingredients used in skin and personal care products. In my case sodium lauryl/laureth sulfate (SLS) has an immediate effect.
'Sulphate' is not the only bad boy. Sometimes a skin care range can develop a name for an ingredient in their product(s) & you have no way of knowing what it actually is.
Here are some chemicals that people with sensitivity issues are advised to avoid
http://suite101.com/article/ten-synthetic-personal-care-ingredients-to-avoid-a256629
Paula Begoun has an excellent ingredient dictionary
http://www.cosmeticscop.com/cosmetic-ingredient-dictionary/A.aspx