The OED confirms naivety is also an English word that's been around since at least the 1700s. I am not implying naïveté is wrong in English, just that there is a simpler option should you so choose.
autocorrect on my ipad went with the more pompous version :-P
You could use it for phishing. It might make users more likely to click through and provide security information if you display their correct full name and even Facebook URL.
You could start Groupon clone right away (presuming you have the deals).
Wonder if you could just spam groupon deals with your affiliate link included?