Whats this about drive water supplementing your fuel with water via a kit?

I got an email today selling plans for a kit that can convert water into what they say is hho a type of hydrogen that my car can use for fuel. So I googled it and got sevral sites saying don’t do it but when I go to them it always goes back to the original sales website. witch means I cant get any real info on this product. Is there anybody out there that has used this on there cars? I mean if this is for real it would be all over the place. I saw something about the techknology on the science channel but befor I modify my car I need to know a lot more than what the people are telling me. If so let me know good or bad. I went to drive water on google and got several sites. check it out and let me know. Thanks!
please c/o the sites then answer