A side note - the SMS confirmation code text should explain what is going to happen when the code is used. Along the lines: "Facebook mobile confirmation code ds3467hj. Note. Entering this code would link this phone to your Facebook account".
Otherwise, if the SMS is just "confirmation code ds3467hj" it is overly easy to create a phishing attack which results in the user (striving to get access to some resource, like a magazine article for example) in entering the code on an attacker web site.
A side note - the SMS confirmation code text should explain what is going to happen when the code is used. Along the lines: "Facebook mobile confirmation code ds3467hj. Note. Entering this code would link this phone to your Facebook account".
Otherwise, if the SMS is just "confirmation code ds3467hj" it is overly easy to create a phishing attack which results in the user (striving to get access to some resource, like a magazine article for example) in entering the code on an attacker web site.