Dd was given an iPhone by a paternal aunt. I checked it and under the advanced website there were some dubious websites porn stuff, fuckbuddy, local slags etc. 
Anyway, I deleted them, and gave the phone to dd. She is 13 and I check the phone randomly and months later there is lots of porn stuff on amongst other teenager stuff. I was devastated. I confronted her and she was devastated. Crying and adamant that she hasn't looked at anything like that. (She knows I check her phone)
The more I looked in to it, the websites are really obscure. You expect a curious child to type in stuff like sex, porn etc, but some of the stuff looks like someone knows what to look for or extensively looks. (Or maybe I'm naive)
I thought maybe that her auntie maybe still has some connection to the iPhone through iTunes??? Is that possible?
I then looked at her iPod and that was even worse, and her auntie has never had that. Very confused.
I kept hold of both for a few weeks. I deleted the stuff on her iPhone and no more have come on. I have kept hold of the iPod and it looks like more things have come on, but can't be sure as the list is very long and I may have just missed it originally.
However there is other things on there that are really 
for a 13 year old to be looking at. Newspapers here, newspapers abroad, teacher website (she is an English teacher in a secondary school) and even Christian forums.
The other thing is, could it be related to her dad? He has iTunes and a iphone, would they maybe crossover? Or am I just clutching at straws? 
I should mention that she has an iTunes account too. If that might be relevant?