Is one of these a scam?
These sites are legit. They both provide information for bitcoin users either newbie or experts. You can learn many things from these sites while you are still a newbie. Just try and read it and you will find many useful in order to join the Bitcoin world
But bitcoin.com is relatively new and from unknown /non-established people, whereas bitcoin.org is being maintained by bitcoin foundation which was originated along with Satoshi Nakamotto.
I do not have any plan to use bitcoin.com for any of purposes like I have come across their one signature campaign is recruiting people from here. (People from here are having account in their forum with same username and proving themselves by signing messages.)