Specific Book??

Okay, there was this book I saw one a review site a few weeks ago. I can't find it now. And that makes me sad. :'-( But please don't cry for me, I just wanted to know if anyone knows it, here is what i remember.

This girl (sorry can't remember he name) and she starts chatting with this guy online. He starts to ask her to do some every weird and perverted things. Um, I know this is like really vague and I'm sorry, I'm putting together a list of YA books. (I know, like I need more books) But if you have any idea please tell me, thanks....